# HG changeset patch
# Parent  5be2231eadfb6de978e93c0ba95469e8a4d54cb0
Description: Add KDE integration to Firefox (toolkit parts)
Author: Wolfgang Rosenauer <wolfgang@rosenauer.org>
Author: Lubos Lunak <lunak@suse.com>
Bug: https://bugzilla.mozilla.org/show_bug.cgi?id=140751
     https://bugzilla.novell.com/show_bug.cgi?id=170055

diff --git a/modules/libpref/Preferences.cpp b/modules/libpref/Preferences.cpp
--- a/modules/libpref/Preferences.cpp
+++ b/modules/libpref/Preferences.cpp
@@ -75,16 +75,17 @@
 #include "nsXPCOMCID.h"
 #include "nsXPCOM.h"
 #include "nsXULAppAPI.h"
 #include "nsZipArchive.h"
 #include "plbase64.h"
 #include "PLDHashTable.h"
 #include "plstr.h"
 #include "prlink.h"
+#include "nsKDEUtils.h"
 
 #ifdef MOZ_CRASHREPORTER
 #include "nsICrashReporter.h"
 #endif
 
 #ifdef XP_WIN
 #include "windows.h"
 #endif
@@ -4324,16 +4325,34 @@ pref_LoadPrefsInDirList(const char* aLis
 {
   nsresult rv;
   nsCOMPtr<nsIProperties> dirSvc(
     do_GetService(NS_DIRECTORY_SERVICE_CONTRACTID, &rv));
   if (NS_FAILED(rv)) {
     return rv;
   }
 
+  // make sure we load these special files after all the others
+  static const char* specialFiles[] = {
+#if defined(XP_UNIX)
+    ""
+#endif
+  };
+
+  if (nsKDEUtils::kdeSession()) {
+    for(int i = 0;
+        i < MOZ_ARRAY_LENGTH(specialFiles);
+        ++i ) {
+      if (*specialFiles[ i ] == '\0') {
+        specialFiles[ i ] = "kde.js";
+        break;
+      }
+    }
+  }
+
   nsCOMPtr<nsISimpleEnumerator> list;
   dirSvc->Get(aListId, NS_GET_IID(nsISimpleEnumerator), getter_AddRefs(list));
   if (!list) {
     return NS_OK;
   }
 
   bool hasMore;
   while (NS_SUCCEEDED(list->HasMoreElements(&hasMore)) && hasMore) {
@@ -4344,17 +4363,17 @@ pref_LoadPrefsInDirList(const char* aLis
     }
 
     nsCOMPtr<nsIFile> path = do_QueryInterface(elem);
     if (!path) {
       continue;
     }
 
     // Do we care if a file provided by this process fails to load?
-    pref_LoadPrefsInDir(path, nullptr, 0);
+    pref_LoadPrefsInDir(path, specialFiles, ArrayLength(specialFiles));
   }
 
   return NS_OK;
 }
 
 static nsresult
 pref_ReadPrefFromJar(nsZipArchive* aJarReader, const char* aName)
 {
@@ -4461,25 +4480,37 @@ pref_InitInitialObjects()
   // application pref files for backwards compatibility.
   static const char* specialFiles[] = {
 #if defined(XP_MACOSX)
     "macprefs.js"
 #elif defined(XP_WIN)
     "winpref.js"
 #elif defined(XP_UNIX)
     "unix.js"
+    , "" // placeholder for KDE  (empty is otherwise harmless)
 #if defined(_AIX)
     ,
     "aix.js"
 #endif
 #elif defined(XP_BEOS)
     "beos.js"
 #endif
   };
 
+  if(nsKDEUtils::kdeSession()) { // TODO what if some setup actually requires the helper?
+    for(int i = 0;
+        i < MOZ_ARRAY_LENGTH(specialFiles);
+        ++i ) {
+      if( *specialFiles[ i ] == '\0' ) {
+        specialFiles[ i ] = "kde.js";
+        break;
+      }
+    }
+  }
+
   rv = pref_LoadPrefsInDir(
     defaultPrefDir, specialFiles, ArrayLength(specialFiles));
   if (NS_FAILED(rv)) {
     NS_WARNING("Error parsing application default preferences.");
   }
 
   // Load jar:$app/omni.jar!/defaults/preferences/*.js
   // or jar:$gre/omni.jar!/defaults/preferences/*.js.
diff --git a/modules/libpref/moz.build b/modules/libpref/moz.build
--- a/modules/libpref/moz.build
+++ b/modules/libpref/moz.build
@@ -27,16 +27,20 @@ XPIDL_MODULE = 'pref'
 EXPORTS.mozilla += [
     'Preferences.h',
 ]
 
 UNIFIED_SOURCES += [
     'Preferences.cpp',
 ]
 
+LOCAL_INCLUDES += [
+     '/toolkit/xre'
+]
+
 include('/ipc/chromium/chromium-config.mozbuild')
 
 FINAL_LIBRARY = 'xul'
 
 DEFINES['OS_ARCH'] = CONFIG['OS_ARCH']
 DEFINES['MOZ_WIDGET_TOOLKIT'] = CONFIG['MOZ_WIDGET_TOOLKIT']
 if CONFIG['MOZ_ENABLE_WEBRENDER']:
     DEFINES['MOZ_ENABLE_WEBRENDER'] = True
diff --git a/python/mozbuild/mozpack/chrome/flags.py b/python/mozbuild/mozpack/chrome/flags.py
--- a/python/mozbuild/mozpack/chrome/flags.py
+++ b/python/mozbuild/mozpack/chrome/flags.py
@@ -220,16 +220,17 @@ class Flags(OrderedDict):
         'contentaccessible': Flag,
         'os': StringFlag,
         'osversion': VersionFlag,
         'abi': StringFlag,
         'platform': Flag,
         'xpcnativewrappers': Flag,
         'tablet': Flag,
         'process': StringFlag,
+        'desktop': StringFlag,
     }
     RE = re.compile(r'([!<>=]+)')
 
     def __init__(self, *flags):
         '''
         Initialize a set of flags given in string form.
            flags = Flags('contentaccessible=yes', 'appversion>=3.5')
         '''
diff --git a/python/mozbuild/mozpack/chrome/manifest.py b/python/mozbuild/mozpack/chrome/manifest.py
--- a/python/mozbuild/mozpack/chrome/manifest.py
+++ b/python/mozbuild/mozpack/chrome/manifest.py
@@ -34,16 +34,17 @@ class ManifestEntry(object):
         'platformversion',
         'os',
         'osversion',
         'abi',
         'xpcnativewrappers',
         'tablet',
         'process',
         'contentaccessible',
+	'desktop',
     ]
 
     def __init__(self, base, *flags):
         '''
         Initialize a manifest entry with the given base path and flags.
         '''
         self.base = base
         self.flags = Flags(*flags)
diff --git a/toolkit/components/downloads/moz.build b/toolkit/components/downloads/moz.build
--- a/toolkit/components/downloads/moz.build
+++ b/toolkit/components/downloads/moz.build
@@ -17,9 +17,13 @@ XPIDL_SOURCES += [
 XPIDL_MODULE = 'downloads'
 
 UNIFIED_SOURCES += [
     'nsDownloadManager.cpp'
 ]
 
 FINAL_LIBRARY = 'xul'
 
+LOCAL_INCLUDES += [
+    '/toolkit/xre'
+]
+
 CXXFLAGS += CONFIG['TK_CFLAGS']
diff --git a/toolkit/content/jar.mn b/toolkit/content/jar.mn
--- a/toolkit/content/jar.mn
+++ b/toolkit/content/jar.mn
@@ -75,29 +75,33 @@ toolkit.jar:
    content/global/bindings/colorpicker.xml     (widgets/colorpicker.xml)
    content/global/bindings/datekeeper.js       (widgets/datekeeper.js)
    content/global/bindings/datepicker.js       (widgets/datepicker.js)
    content/global/bindings/datetimepicker.xml  (widgets/datetimepicker.xml)
    content/global/bindings/datetimepopup.xml   (widgets/datetimepopup.xml)
    content/global/bindings/datetimebox.xml     (widgets/datetimebox.xml)
    content/global/bindings/datetimebox.css     (widgets/datetimebox.css)
 *  content/global/bindings/dialog.xml          (widgets/dialog.xml)
+*  content/global/bindings/dialog-kde.xml      (widgets/dialog-kde.xml)
+% override chrome://global/content/bindings/dialog.xml chrome://global/content/bindings/dialog-kde.xml desktop=kde
    content/global/bindings/editor.xml          (widgets/editor.xml)
    content/global/bindings/expander.xml        (widgets/expander.xml)
    content/global/bindings/filefield.xml       (widgets/filefield.xml)
 *  content/global/bindings/findbar.xml         (widgets/findbar.xml)
    content/global/bindings/general.xml         (widgets/general.xml)
    content/global/bindings/groupbox.xml        (widgets/groupbox.xml)
    content/global/bindings/listbox.xml         (widgets/listbox.xml)
    content/global/bindings/menu.xml            (widgets/menu.xml)
    content/global/bindings/menulist.xml        (widgets/menulist.xml)
    content/global/bindings/notification.xml    (widgets/notification.xml)
    content/global/bindings/numberbox.xml       (widgets/numberbox.xml)
    content/global/bindings/popup.xml           (widgets/popup.xml)
 *  content/global/bindings/preferences.xml     (widgets/preferences.xml)
+*  content/global/bindings/preferences-kde.xml (widgets/preferences-kde.xml)
+% override chrome://global/content/bindings/preferences.xml chrome://global/content/bindings/preferences-kde.xml desktop=kde
    content/global/bindings/progressmeter.xml   (widgets/progressmeter.xml)
    content/global/bindings/radio.xml           (widgets/radio.xml)
    content/global/bindings/remote-browser.xml  (widgets/remote-browser.xml)
    content/global/bindings/resizer.xml         (widgets/resizer.xml)
    content/global/bindings/richlistbox.xml     (widgets/richlistbox.xml)
    content/global/bindings/scale.xml           (widgets/scale.xml)
    content/global/bindings/scrollbar.xml       (widgets/scrollbar.xml)
    content/global/bindings/scrollbox.xml       (widgets/scrollbox.xml)
diff --git a/toolkit/content/widgets/dialog-kde.xml b/toolkit/content/widgets/dialog-kde.xml
new file mode 100644
--- /dev/null
+++ b/toolkit/content/widgets/dialog-kde.xml
@@ -0,0 +1,459 @@
+<?xml version="1.0"?>
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+
+<bindings id="dialogBindings"
+          xmlns="http://www.mozilla.org/xbl"
+          xmlns:xul="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul"
+          xmlns:xbl="http://www.mozilla.org/xbl">
+
+  <binding id="dialog" extends="chrome://global/content/bindings/general.xml#root-element">
+    <resources>
+      <stylesheet src="chrome://global/skin/dialog.css"/>
+    </resources>
+    <content>
+      <xul:vbox class="box-inherit dialog-content-box" flex="1">
+        <children/>
+      </xul:vbox>
+
+      <xul:hbox class="dialog-button-box" anonid="buttons"
+                xbl:inherits="pack=buttonpack,align=buttonalign,dir=buttondir,orient=buttonorient"
+#ifdef XP_UNIX_GNOME
+                >
+        <xul:button dlgtype="disclosure" class="dialog-button" hidden="true"/>
+        <xul:button dlgtype="help" class="dialog-button" hidden="true"/>
+        <xul:button dlgtype="extra2" class="dialog-button" hidden="true"/>
+        <xul:button dlgtype="extra1" class="dialog-button" hidden="true"/>
+        <xul:spacer anonid="spacer" flex="1"/>
+        <xul:button dlgtype="cancel" class="dialog-button"/>
+        <xul:button dlgtype="accept" class="dialog-button" xbl:inherits="disabled=buttondisabledaccept"/>
+#elif XP_UNIX
+                >
+        <xul:button dlgtype="help" class="dialog-button" hidden="true"/>
+        <xul:button dlgtype="extra2" class="dialog-button" hidden="true"/>
+        <xul:spacer anonid="spacer" flex="1"/>
+        <xul:button dlgtype="accept" class="dialog-button" xbl:inherits="disabled=buttondisabledaccept"/>
+        <xul:button dlgtype="extra1" class="dialog-button" hidden="true"/>
+        <xul:button dlgtype="cancel" class="dialog-button"/>
+        <xul:button dlgtype="disclosure" class="dialog-button" hidden="true"/>
+#else
+                pack="end">
+        <xul:button dlgtype="extra2" class="dialog-button" hidden="true"/>
+        <xul:spacer anonid="spacer" flex="1" hidden="true"/>
+        <xul:button dlgtype="accept" class="dialog-button" xbl:inherits="disabled=buttondisabledaccept"/>
+        <xul:button dlgtype="extra1" class="dialog-button" hidden="true"/>
+        <xul:button dlgtype="cancel" class="dialog-button"/>
+        <xul:button dlgtype="help" class="dialog-button" hidden="true"/>
+        <xul:button dlgtype="disclosure" class="dialog-button" hidden="true"/>
+#endif
+      </xul:hbox>
+    </content>
+
+    <implementation>
+      <field name="_mStrBundle">null</field>
+      <field name="_closeHandler">(function(event) {
+        if (!document.documentElement.cancelDialog())
+          event.preventDefault();
+      })</field>
+
+      <property name="buttons"
+                onget="return this.getAttribute('buttons');"
+                onset="this._configureButtons(val); return val;"/>
+
+      <property name="defaultButton">
+        <getter>
+        <![CDATA[
+          if (this.hasAttribute("defaultButton"))
+            return this.getAttribute("defaultButton");
+          return "accept";  // default to the accept button
+        ]]>
+        </getter>
+        <setter>
+        <![CDATA[
+          this._setDefaultButton(val);
+          return val;
+        ]]>
+        </setter>
+      </property>
+
+      <method name="acceptDialog">
+        <body>
+        <![CDATA[
+          return this._doButtonCommand("accept");
+        ]]>
+        </body>
+      </method>
+
+      <method name="cancelDialog">
+        <body>
+        <![CDATA[
+          return this._doButtonCommand("cancel");
+        ]]>
+        </body>
+      </method>
+
+      <method name="getButton">
+        <parameter name="aDlgType"/>
+        <body>
+        <![CDATA[
+          return this._buttons[aDlgType];
+        ]]>
+        </body>
+      </method>
+
+      <method name="moveToAlertPosition">
+        <body>
+        <![CDATA[
+          // hack. we need this so the window has something like its final size
+          if (window.outerWidth == 1) {
+            dump("Trying to position a sizeless window; caller should have called sizeToContent() or sizeTo(). See bug 75649.\n");
+            sizeToContent();
+          }
+
+          if (opener) {
+            var xOffset = (opener.outerWidth - window.outerWidth) / 2;
+            var yOffset = opener.outerHeight / 5;
+
+            var newX = opener.screenX + xOffset;
+            var newY = opener.screenY + yOffset;
+          } else {
+            newX = (screen.availWidth - window.outerWidth) / 2;
+            newY = (screen.availHeight - window.outerHeight) / 2;
+          }
+
+          // ensure the window is fully onscreen (if smaller than the screen)
+          if (newX < screen.availLeft)
+            newX = screen.availLeft + 20;
+          if ((newX + window.outerWidth) > (screen.availLeft + screen.availWidth))
+            newX = (screen.availLeft + screen.availWidth) - window.outerWidth - 20;
+
+          if (newY < screen.availTop)
+            newY = screen.availTop + 20;
+          if ((newY + window.outerHeight) > (screen.availTop + screen.availHeight))
+            newY = (screen.availTop + screen.availHeight) - window.outerHeight - 60;
+
+          window.moveTo( newX, newY );
+        ]]>
+        </body>
+      </method>
+
+      <method name="centerWindowOnScreen">
+        <body>
+        <![CDATA[
+          var xOffset = screen.availWidth / 2 - window.outerWidth / 2;
+          var yOffset = screen.availHeight / 2 - window.outerHeight / 2;
+
+          xOffset = xOffset > 0 ? xOffset : 0;
+          yOffset = yOffset > 0 ? yOffset : 0;
+          window.moveTo(xOffset, yOffset);
+        ]]>
+        </body>
+      </method>
+
+      <constructor>
+      <![CDATA[
+        this._configureButtons(this.buttons);
+
+        // listen for when window is closed via native close buttons
+        window.addEventListener("close", this._closeHandler);
+
+        // for things that we need to initialize after onload fires
+        window.addEventListener("load", this.postLoadInit);
+
+        window.moveToAlertPosition = this.moveToAlertPosition;
+        window.centerWindowOnScreen = this.centerWindowOnScreen;
+      ]]>
+      </constructor>
+
+      <method name="postLoadInit">
+        <parameter name="aEvent"/>
+        <body>
+        <![CDATA[
+          function focusInit() {
+            const dialog = document.documentElement;
+            const defaultButton = dialog.getButton(dialog.defaultButton);
+            // give focus to the first focusable element in the dialog
+            if (!document.commandDispatcher.focusedElement) {
+              document.commandDispatcher.advanceFocusIntoSubtree(dialog);
+
+              var focusedElt = document.commandDispatcher.focusedElement;
+              if (focusedElt) {
+                var initialFocusedElt = focusedElt;
+                while (focusedElt.localName == "tab" ||
+                       focusedElt.getAttribute("noinitialfocus") == "true") {
+                  document.commandDispatcher.advanceFocusIntoSubtree(focusedElt);
+                  focusedElt = document.commandDispatcher.focusedElement;
+                  if (focusedElt == initialFocusedElt) {
+                    if (focusedElt.getAttribute("noinitialfocus") == "true") {
+                      focusedElt.blur();
+                    }
+                    break;
+                  }
+                }
+
+                if (initialFocusedElt.localName == "tab") {
+                  if (focusedElt.hasAttribute("dlgtype")) {
+                    // We don't want to focus on anonymous OK, Cancel, etc. buttons,
+                    // so return focus to the tab itself
+                    initialFocusedElt.focus();
+                  }
+                } else if (!/Mac/.test(navigator.platform) &&
+                           focusedElt.hasAttribute("dlgtype") && focusedElt != defaultButton) {
+                  defaultButton.focus();
+                }
+              }
+            }
+
+            try {
+              if (defaultButton)
+                window.notifyDefaultButtonLoaded(defaultButton);
+            } catch (e) { }
+          }
+
+          // Give focus after onload completes, see bug 103197.
+          setTimeout(focusInit, 0);
+        ]]>
+        </body>
+      </method>
+
+      <property name="mStrBundle">
+        <getter>
+        <![CDATA[
+          if (!this._mStrBundle) {
+            // need to create string bundle manually instead of using <xul:stringbundle/>
+            // see bug 63370 for details
+            this._mStrBundle = Components.classes["@mozilla.org/intl/stringbundle;1"]
+                                         .getService(Components.interfaces.nsIStringBundleService)
+                                         .createBundle("chrome://global/locale/dialog.properties");
+          }
+          return this._mStrBundle;
+        ]]></getter>
+      </property>
+
+      <method name="_configureButtons">
+        <parameter name="aButtons"/>
+        <body>
+        <![CDATA[
+          // by default, get all the anonymous button elements
+          var buttons = {};
+          this._buttons = buttons;
+          buttons.accept = document.getAnonymousElementByAttribute(this, "dlgtype", "accept");
+          buttons.cancel = document.getAnonymousElementByAttribute(this, "dlgtype", "cancel");
+          buttons.extra1 = document.getAnonymousElementByAttribute(this, "dlgtype", "extra1");
+          buttons.extra2 = document.getAnonymousElementByAttribute(this, "dlgtype", "extra2");
+          buttons.help = document.getAnonymousElementByAttribute(this, "dlgtype", "help");
+          buttons.disclosure = document.getAnonymousElementByAttribute(this, "dlgtype", "disclosure");
+
+          // look for any overriding explicit button elements
+          var exBtns = this.getElementsByAttribute("dlgtype", "*");
+          var dlgtype;
+          var i;
+          for (i = 0; i < exBtns.length; ++i) {
+            dlgtype = exBtns[i].getAttribute("dlgtype");
+            buttons[dlgtype].hidden = true; // hide the anonymous button
+            buttons[dlgtype] = exBtns[i];
+          }
+
+          // add the label and oncommand handler to each button
+          for (dlgtype in buttons) {
+            var button = buttons[dlgtype];
+            button.addEventListener("command", this._handleButtonCommand, true);
+
+            // don't override custom labels with pre-defined labels on explicit buttons
+            if (!button.hasAttribute("label")) {
+              // dialog attributes override the default labels in dialog.properties
+              if (this.hasAttribute("buttonlabel" + dlgtype)) {
+                button.setAttribute("label", this.getAttribute("buttonlabel" + dlgtype));
+                if (this.hasAttribute("buttonaccesskey" + dlgtype))
+                  button.setAttribute("accesskey", this.getAttribute("buttonaccesskey" + dlgtype));
+              } else if (dlgtype != "extra1" && dlgtype != "extra2") {
+                button.setAttribute("label", this.mStrBundle.GetStringFromName("button-" + dlgtype));
+                var accessKey = this.mStrBundle.GetStringFromName("accesskey-" + dlgtype);
+                if (accessKey)
+                  button.setAttribute("accesskey", accessKey);
+              }
+            }
+            // allow specifying alternate icons in the dialog header
+            if (!button.hasAttribute("icon")) {
+              // if there's an icon specified, use that
+              if (this.hasAttribute("buttonicon" + dlgtype))
+                button.setAttribute("icon", this.getAttribute("buttonicon" + dlgtype));
+              // otherwise set defaults
+              else
+                switch (dlgtype) {
+                  case "accept":
+                    button.setAttribute("icon", "accept");
+                    break;
+                  case "cancel":
+                    button.setAttribute("icon", "cancel");
+                    break;
+                  case "disclosure":
+                    button.setAttribute("icon", "properties");
+                    break;
+                  case "help":
+                    button.setAttribute("icon", "help");
+                    break;
+                  default:
+                    break;
+                }
+            }
+          }
+
+          // ensure that hitting enter triggers the default button command
+          this.defaultButton = this.defaultButton;
+
+          // if there is a special button configuration, use it
+          if (aButtons) {
+            // expect a comma delimited list of dlgtype values
+            var list = aButtons.split(",");
+
+            // mark shown dlgtypes as true
+            var shown = { accept: false, cancel: false, help: false,
+                          disclosure: false, extra1: false, extra2: false };
+            for (i = 0; i < list.length; ++i)
+              shown[list[i].replace(/ /g, "")] = true;
+
+            // hide/show the buttons we want
+            for (dlgtype in buttons)
+              buttons[dlgtype].hidden = !shown[dlgtype];
+
+            // show the spacer on Windows only when the extra2 button is present
+            if (/Win/.test(navigator.platform)) {
+              var spacer = document.getAnonymousElementByAttribute(this, "anonid", "spacer");
+              spacer.removeAttribute("hidden");
+              spacer.setAttribute("flex", shown.extra2 ? "1" : "0");
+            }
+          }
+        ]]>
+        </body>
+      </method>
+
+      <method name="_setDefaultButton">
+        <parameter name="aNewDefault"/>
+        <body>
+        <![CDATA[
+          // remove the default attribute from the previous default button, if any
+          var oldDefaultButton = this.getButton(this.defaultButton);
+          if (oldDefaultButton)
+            oldDefaultButton.removeAttribute("default");
+
+          var newDefaultButton = this.getButton(aNewDefault);
+          if (newDefaultButton) {
+            this.setAttribute("defaultButton", aNewDefault);
+            newDefaultButton.setAttribute("default", "true");
+          } else {
+            this.setAttribute("defaultButton", "none");
+            if (aNewDefault != "none")
+              dump("invalid new default button: " + aNewDefault + ", assuming: none\n");
+          }
+        ]]>
+        </body>
+      </method>
+
+      <method name="_handleButtonCommand">
+        <parameter name="aEvent"/>
+        <body>
+        <![CDATA[
+          return document.documentElement._doButtonCommand(
+                                        aEvent.target.getAttribute("dlgtype"));
+        ]]>
+        </body>
+      </method>
+
+      <method name="_doButtonCommand">
+        <parameter name="aDlgType"/>
+        <body>
+        <![CDATA[
+          var button = this.getButton(aDlgType);
+          if (!button.disabled) {
+            var noCancel = this._fireButtonEvent(aDlgType);
+            if (noCancel) {
+              if (aDlgType == "accept" || aDlgType == "cancel") {
+                var closingEvent = new CustomEvent("dialogclosing", {
+                  bubbles: true,
+                  detail: { button: aDlgType },
+                });
+                this.dispatchEvent(closingEvent);
+                window.close();
+              }
+            }
+            return noCancel;
+          }
+          return true;
+        ]]>
+        </body>
+      </method>
+
+      <method name="_fireButtonEvent">
+        <parameter name="aDlgType"/>
+        <body>
+        <![CDATA[
+          var event = document.createEvent("Events");
+          event.initEvent("dialog" + aDlgType, true, true);
+
+          // handle dom event handlers
+          var noCancel = this.dispatchEvent(event);
+
+          // handle any xml attribute event handlers
+          var handler = this.getAttribute("ondialog" + aDlgType);
+          if (handler != "") {
+            var fn = new Function("event", handler);
+            var returned = fn(event);
+            if (returned == false)
+              noCancel = false;
+          }
+
+          return noCancel;
+        ]]>
+        </body>
+      </method>
+
+      <method name="_hitEnter">
+        <parameter name="evt"/>
+        <body>
+        <![CDATA[
+          if (evt.defaultPrevented)
+            return;
+
+          var btn = this.getButton(this.defaultButton);
+          if (btn)
+            this._doButtonCommand(this.defaultButton);
+        ]]>
+        </body>
+      </method>
+
+    </implementation>
+
+    <handlers>
+      <handler event="keypress" keycode="VK_RETURN"
+               group="system" action="this._hitEnter(event);"/>
+      <handler event="keypress" keycode="VK_ESCAPE" group="system">
+        if (!event.defaultPrevented)
+          this.cancelDialog();
+      </handler>
+#ifdef XP_MACOSX
+      <handler event="keypress" key="." modifiers="meta" phase="capturing" action="this.cancelDialog();"/>
+#else
+      <handler event="focus" phase="capturing">
+        var btn = this.getButton(this.defaultButton);
+        if (btn)
+          btn.setAttribute("default", event.originalTarget == btn || !(event.originalTarget instanceof Components.interfaces.nsIDOMXULButtonElement));
+      </handler>
+#endif
+    </handlers>
+
+  </binding>
+
+  <binding id="dialogheader">
+    <resources>
+      <stylesheet src="chrome://global/skin/dialog.css"/>
+    </resources>
+    <content>
+      <xul:label class="dialogheader-title" xbl:inherits="value=title,crop" crop="right" flex="1"/>
+      <xul:label class="dialogheader-description" xbl:inherits="value=description"/>
+    </content>
+  </binding>
+
+</bindings>
diff --git a/toolkit/content/widgets/preferences-kde.xml b/toolkit/content/widgets/preferences-kde.xml
new file mode 100644
--- /dev/null
+++ b/toolkit/content/widgets/preferences-kde.xml
@@ -0,0 +1,1409 @@
+<?xml version="1.0"?>
+
+<!DOCTYPE bindings [
+  <!ENTITY % preferencesDTD SYSTEM "chrome://global/locale/preferences.dtd">
+  %preferencesDTD;
+  <!ENTITY % globalKeysDTD SYSTEM "chrome://global/locale/globalKeys.dtd">
+  %globalKeysDTD;
+]>
+
+<bindings id="preferencesBindings"
+          xmlns="http://www.mozilla.org/xbl"
+          xmlns:xbl="http://www.mozilla.org/xbl"
+          xmlns:xul="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
+
+#
+# = Preferences Window Framework
+#
+#   The syntax for use looks something like:
+#
+#   <prefwindow>
+#     <prefpane id="prefPaneA">
+#       <preferences>
+#         <preference id="preference1" name="app.preference1" type="bool" onchange="foo();"/>
+#         <preference id="preference2" name="app.preference2" type="bool" useDefault="true"/>
+#       </preferences>
+#       <checkbox label="Preference" preference="preference1"/>
+#     </prefpane>
+#   </prefwindow>
+#
+
+  <binding id="preferences">
+    <implementation implements="nsIObserver">
+      <method name="_constructAfterChildren">
+      <body>
+      <![CDATA[
+      // This method will be called after the last of the child
+      // <preference> elements is constructed. Its purpose is to propagate
+      // the values to the associated form elements. Sometimes the code for
+      // some <preference> initializers depend on other <preference> elements
+      // being initialized so we wait and call updateElements on all of them
+      // once the last one has been constructed. See bugs 997570 and 992185.
+
+      var elements = this.getElementsByTagName("preference");
+      for (let element of elements) {
+        element.updateElements();
+      }
+
+      this._constructAfterChildrenCalled = true;
+      ]]>
+      </body>
+      </method>
+      <method name="observe">
+        <parameter name="aSubject"/>
+        <parameter name="aTopic"/>
+        <parameter name="aData"/>
+        <body>
+        <![CDATA[
+          for (var i = 0; i < this.childNodes.length; ++i) {
+            var preference = this.childNodes[i];
+            if (preference.name == aData) {
+              preference.value = preference.valueFromPreferences;
+            }
+          }
+        ]]>
+        </body>
+      </method>
+
+      <method name="fireChangedEvent">
+        <parameter name="aPreference"/>
+        <body>
+        <![CDATA[
+          // Value changed, synthesize an event
+          try {
+            var event = document.createEvent("Events");
+            event.initEvent("change", true, true);
+            aPreference.dispatchEvent(event);
+          } catch (e) {
+            Components.utils.reportError(e);
+          }
+        ]]>
+        </body>
+      </method>
+
+      <field name="service">
+        Components.classes["@mozilla.org/preferences-service;1"]
+                  .getService(Components.interfaces.nsIPrefService);
+      </field>
+      <field name="rootBranch">
+        Components.classes["@mozilla.org/preferences-service;1"]
+                  .getService(Components.interfaces.nsIPrefBranch);
+      </field>
+      <field name="defaultBranch">
+        this.service.getDefaultBranch("");
+      </field>
+      <field name="rootBranchInternal">
+        Components.classes["@mozilla.org/preferences-service;1"]
+                  .getService(Components.interfaces.nsIPrefBranch);
+      </field>
+      <property name="type" readonly="true">
+        <getter>
+          <![CDATA[
+            return document.documentElement.type || "";
+          ]]>
+        </getter>
+      </property>
+      <property name="instantApply" readonly="true">
+        <getter>
+          <![CDATA[
+            var doc = document.documentElement;
+            return this.type == "child" ? doc.instantApply
+                                        : doc.instantApply || this.rootBranch.getBoolPref("browser.preferences.instantApply");
+          ]]>
+        </getter>
+      </property>
+
+      <!-- We want to call _constructAfterChildren after all child
+           <preference> elements have been constructed. To do this, we get
+           and store the node list of all child <preference> elements in the
+           constructor, and maintain a count which is incremented in the
+           constructor of <preference>. _constructAfterChildren is called
+           when the count matches the length of the list. -->
+      <field name="_constructedChildrenCount">0</field>
+      <field name="_preferenceChildren">null</field>
+      <!-- Some <preference> elements are added dynamically after
+           _constructAfterChildren has already been called - we want to
+           avoid looping over all of them again in this case so we remember
+           if we already called it. -->
+      <field name="_constructAfterChildrenCalled">false</field>
+      <constructor>
+      <![CDATA[
+        this._preferenceChildren = this.getElementsByTagName("preference");
+      ]]>
+      </constructor>
+    </implementation>
+  </binding>
+
+  <binding id="preference">
+    <implementation>
+      <constructor>
+      <![CDATA[
+        // if the element has been inserted without the name attribute set,
+        // we have nothing to do here
+        if (!this.name)
+          return;
+
+        this.preferences.rootBranchInternal
+            .addObserver(this.name, this.preferences);
+        // In non-instant apply mode, we must try and use the last saved state
+        // from any previous opens of a child dialog instead of the value from
+        // preferences, to pick up any edits a user may have made.
+
+        var secMan = Components.classes["@mozilla.org/scriptsecuritymanager;1"]
+                    .getService(Components.interfaces.nsIScriptSecurityManager);
+        if (this.preferences.type == "child" &&
+            !this.instantApply && window.opener &&
+            secMan.isSystemPrincipal(window.opener.document.nodePrincipal)) {
+          var pdoc = window.opener.document;
+
+          // Try to find a preference element for the same preference.
+          var preference = null;
+          var parentPreferences = pdoc.getElementsByTagName("preferences");
+          for (var k = 0; (k < parentPreferences.length && !preference); ++k) {
+            var parentPrefs = parentPreferences[k]
+                                    .getElementsByAttribute("name", this.name);
+            for (var l = 0; (l < parentPrefs.length && !preference); ++l) {
+              if (parentPrefs[l].localName == "preference")
+                preference = parentPrefs[l];
+            }
+          }
+
+          // Don't use the value setter here, we don't want updateElements to be prematurely fired.
+          this._value = preference ? preference.value : this.valueFromPreferences;
+        } else {
+          this._value = this.valueFromPreferences;
+        }
+        if (this.preferences._constructAfterChildrenCalled) {
+          // This <preference> was added after _constructAfterChildren() was already called.
+          // We can directly call updateElements().
+          this.updateElements();
+          return;
+        }
+        this.preferences._constructedChildrenCount++;
+        if (this.preferences._constructedChildrenCount ==
+            this.preferences._preferenceChildren.length) {
+          // This is the last <preference>, time to updateElements() on all of them.
+          this.preferences._constructAfterChildren();
+        }
+      ]]>
+      </constructor>
+      <destructor>
+        this.preferences.rootBranchInternal
+            .removeObserver(this.name, this.preferences);
+      </destructor>
+      <field name="_constructed">false</field>
+      <property name="instantApply">
+        <getter>
+          if (this.getAttribute("instantApply") == "false")
+            return false;
+          return this.getAttribute("instantApply") == "true" || this.preferences.instantApply;
+        </getter>
+      </property>
+
+      <property name="preferences" onget="return this.parentNode"/>
+      <property name="name" onget="return this.getAttribute('name');">
+        <setter>
+          if (val == this.name)
+            return val;
+
+          this.preferences.rootBranchInternal
+              .removeObserver(this.name, this.preferences);
+          this.setAttribute("name", val);
+          this.preferences.rootBranchInternal
+              .addObserver(val, this.preferences);
+
+          return val;
+        </setter>
+      </property>
+      <property name="type" onget="return this.getAttribute('type');"
+                            onset="this.setAttribute('type', val); return val;"/>
+      <property name="inverted" onget="return this.getAttribute('inverted') == 'true';"
+                                onset="this.setAttribute('inverted', val); return val;"/>
+      <property name="readonly" onget="return this.getAttribute('readonly') == 'true';"
+                                onset="this.setAttribute('readonly', val); return val;"/>
+
+      <field name="_value">null</field>
+      <method name="_setValue">
+        <parameter name="aValue"/>
+        <body>
+        <![CDATA[
+          if (this.value !== aValue) {
+            this._value = aValue;
+            if (this.instantApply)
+              this.valueFromPreferences = aValue;
+            this.preferences.fireChangedEvent(this);
+          }
+          return aValue;
+        ]]>
+        </body>
+      </method>
+      <property name="value" onget="return this._value" onset="return this._setValue(val);"/>
+
+      <property name="locked">
+        <getter>
+          return this.preferences.rootBranch.prefIsLocked(this.name);
+        </getter>
+      </property>
+
+      <property name="disabled">
+        <getter>
+          return this.getAttribute("disabled") == "true";
+        </getter>
+        <setter>
+        <![CDATA[
+          if (val)
+            this.setAttribute("disabled", "true");
+          else
+            this.removeAttribute("disabled");
+
+          if (!this.id)
+            return val;
+
+          var elements = document.getElementsByAttribute("preference", this.id);
+          for (var i = 0; i < elements.length; ++i) {
+            elements[i].disabled = val;
+
+            var labels = document.getElementsByAttribute("control", elements[i].id);
+            for (var j = 0; j < labels.length; ++j)
+              labels[j].disabled = val;
+          }
+
+          return val;
+        ]]>
+        </setter>
+      </property>
+
+      <property name="tabIndex">
+        <getter>
+          return parseInt(this.getAttribute("tabindex"));
+        </getter>
+        <setter>
+        <![CDATA[
+          if (val)
+            this.setAttribute("tabindex", val);
+          else
+            this.removeAttribute("tabindex");
+
+          if (!this.id)
+            return val;
+
+          var elements = document.getElementsByAttribute("preference", this.id);
+          for (var i = 0; i < elements.length; ++i) {
+            elements[i].tabIndex = val;
+
+            var labels = document.getElementsByAttribute("control", elements[i].id);
+            for (var j = 0; j < labels.length; ++j)
+              labels[j].tabIndex = val;
+          }
+
+          return val;
+        ]]>
+        </setter>
+      </property>
+
+      <property name="hasUserValue">
+        <getter>
+        <![CDATA[
+          return this.preferences.rootBranch.prefHasUserValue(this.name) &&
+                 this.value !== undefined;
+        ]]>
+        </getter>
+      </property>
+
+      <method name="reset">
+        <body>
+          // defer reset until preference update
+          this.value = undefined;
+        </body>
+      </method>
+
+      <field name="_useDefault">false</field>
+      <property name="defaultValue">
+        <getter>
+        <![CDATA[
+          this._useDefault = true;
+          var val = this.valueFromPreferences;
+          this._useDefault = false;
+          return val;
+        ]]>
+        </getter>
+      </property>
+
+      <property name="_branch">
+        <getter>
+          return this._useDefault ? this.preferences.defaultBranch : this.preferences.rootBranch;
+        </getter>
+      </property>
+
+      <field name="batching">false</field>
+
+      <method name="_reportUnknownType">
+        <body>
+        <![CDATA[
+          var consoleService = Components.classes["@mozilla.org/consoleservice;1"]
+                                         .getService(Components.interfaces.nsIConsoleService);
+          var msg = "<preference> with id='" + this.id + "' and name='" +
+                    this.name + "' has unknown type '" + this.type + "'.";
+          consoleService.logStringMessage(msg);
+        ]]>
+        </body>
+      </method>
+
+      <property name="valueFromPreferences">
+        <getter>
+        <![CDATA[
+          try {
+            // Force a resync of value with preferences.
+            switch (this.type) {
+            case "int":
+              return this._branch.getIntPref(this.name);
+            case "bool":
+              var val = this._branch.getBoolPref(this.name);
+              return this.inverted ? !val : val;
+            case "wstring":
+              return this._branch
+                         .getComplexValue(this.name, Components.interfaces.nsIPrefLocalizedString)
+                         .data;
+            case "string":
+            case "unichar":
+              return this._branch.getStringPref(this.name);
+            case "fontname":
+              var family = this._branch.getStringPref(this.name);
+              var fontEnumerator = Components.classes["@mozilla.org/gfx/fontenumerator;1"]
+                                             .createInstance(Components.interfaces.nsIFontEnumerator);
+              return fontEnumerator.getStandardFamilyName(family);
+            case "file":
+              var f = this._branch
+                          .getComplexValue(this.name, Components.interfaces.nsIFile);
+              return f;
+            default:
+              this._reportUnknownType();
+            }
+          } catch (e) { }
+          return null;
+        ]]>
+        </getter>
+        <setter>
+        <![CDATA[
+          // Exit early if nothing to do.
+          if (this.readonly || this.valueFromPreferences == val)
+            return val;
+
+          // The special value undefined means 'reset preference to default'.
+          if (val === undefined) {
+            this.preferences.rootBranch.clearUserPref(this.name);
+            return val;
+          }
+
+          // Force a resync of preferences with value.
+          switch (this.type) {
+          case "int":
+            this.preferences.rootBranch.setIntPref(this.name, val);
+            break;
+          case "bool":
+            this.preferences.rootBranch.setBoolPref(this.name, this.inverted ? !val : val);
+            break;
+          case "wstring":
+            var pls = Components.classes["@mozilla.org/pref-localizedstring;1"]
+                                .createInstance(Components.interfaces.nsIPrefLocalizedString);
+            pls.data = val;
+            this.preferences.rootBranch
+                .setComplexValue(this.name, Components.interfaces.nsIPrefLocalizedString, pls);
+            break;
+          case "string":
+          case "unichar":
+          case "fontname":
+            this.preferences.rootBranch.setStringPref(this.name, val);
+            break;
+          case "file":
+            var lf;
+            if (typeof(val) == "string") {
+              lf = Components.classes["@mozilla.org/file/local;1"]
+                             .createInstance(Components.interfaces.nsIFile);
+              lf.persistentDescriptor = val;
+              if (!lf.exists())
+                lf.initWithPath(val);
+            } else
+              lf = val.QueryInterface(Components.interfaces.nsIFile);
+            this.preferences.rootBranch
+                .setComplexValue(this.name, Components.interfaces.nsIFile, lf);
+            break;
+          default:
+            this._reportUnknownType();
+          }
+          if (!this.batching)
+            this.preferences.service.savePrefFile(null);
+          return val;
+        ]]>
+        </setter>
+      </property>
+
+      <method name="setElementValue">
+        <parameter name="aElement"/>
+        <body>
+        <![CDATA[
+          if (this.locked)
+            aElement.disabled = true;
+
+          if (!this.isElementEditable(aElement))
+            return;
+
+          var rv = undefined;
+          if (aElement.hasAttribute("onsyncfrompreference")) {
+            // Value changed, synthesize an event
+            try {
+              var event = document.createEvent("Events");
+              event.initEvent("syncfrompreference", true, true);
+              var f = new Function("event",
+                                   aElement.getAttribute("onsyncfrompreference"));
+              rv = f.call(aElement, event);
+            } catch (e) {
+              Components.utils.reportError(e);
+            }
+          }
+          var val = rv;
+          if (val === undefined)
+            val = this.instantApply ? this.valueFromPreferences : this.value;
+          // if the preference is marked for reset, show default value in UI
+          if (val === undefined)
+            val = this.defaultValue;
+
+          /**
+           * Initialize a UI element property with a value. Handles the case
+           * where an element has not yet had a XBL binding attached for it and
+           * the property setter does not yet exist by setting the same attribute
+           * on the XUL element using DOM apis and assuming the element's
+           * constructor or property getters appropriately handle this state.
+           */
+          function setValue(element, attribute, value) {
+            if (attribute in element)
+              element[attribute] = value;
+            else
+              element.setAttribute(attribute, value);
+          }
+          if (aElement.localName == "checkbox" ||
+              aElement.localName == "listitem")
+            setValue(aElement, "checked", val);
+          else if (aElement.localName == "colorpicker")
+            setValue(aElement, "color", val);
+          else if (aElement.localName == "textbox") {
+            // XXXmano Bug 303998: Avoid a caret placement issue if either the
+            // preference observer or its setter calls updateElements as a result
+            // of the input event handler.
+            if (aElement.value !== val)
+              setValue(aElement, "value", val);
+          } else
+            setValue(aElement, "value", val);
+        ]]>
+        </body>
+      </method>
+
+      <method name="getElementValue">
+        <parameter name="aElement"/>
+        <body>
+        <![CDATA[
+          if (aElement.hasAttribute("onsynctopreference")) {
+            // Value changed, synthesize an event
+            try {
+              var event = document.createEvent("Events");
+              event.initEvent("synctopreference", true, true);
+              var f = new Function("event",
+                                   aElement.getAttribute("onsynctopreference"));
+              var rv = f.call(aElement, event);
+              if (rv !== undefined)
+                return rv;
+            } catch (e) {
+              Components.utils.reportError(e);
+            }
+          }
+
+          /**
+           * Read the value of an attribute from an element, assuming the
+           * attribute is a property on the element's node API. If the property
+           * is not present in the API, then assume its value is contained in
+           * an attribute, as is the case before a binding has been attached.
+           */
+          function getValue(element, attribute) {
+            if (attribute in element)
+              return element[attribute];
+            return element.getAttribute(attribute);
+          }
+          if (aElement.localName == "checkbox" ||
+              aElement.localName == "listitem")
+            var value = getValue(aElement, "checked");
+          else if (aElement.localName == "colorpicker")
+            value = getValue(aElement, "color");
+          else
+            value = getValue(aElement, "value");
+
+          switch (this.type) {
+          case "int":
+            return parseInt(value, 10) || 0;
+          case "bool":
+            return typeof(value) == "boolean" ? value : value == "true";
+          }
+          return value;
+        ]]>
+        </body>
+      </method>
+
+      <method name="isElementEditable">
+        <parameter name="aElement"/>
+        <body>
+        <![CDATA[
+          switch (aElement.localName) {
+          case "checkbox":
+          case "colorpicker":
+          case "radiogroup":
+          case "textbox":
+          case "listitem":
+          case "listbox":
+          case "menulist":
+            return true;
+          }
+          return aElement.getAttribute("preference-editable") == "true";
+        ]]>
+        </body>
+      </method>
+
+      <method name="updateElements">
+        <body>
+        <![CDATA[
+          if (!this.id)
+            return;
+
+          // This "change" event handler tracks changes made to preferences by
+          // sources other than the user in this window.
+          var elements = document.getElementsByAttribute("preference", this.id);
+          for (var i = 0; i < elements.length; ++i)
+            this.setElementValue(elements[i]);
+        ]]>
+        </body>
+      </method>
+    </implementation>
+
+    <handlers>
+      <handler event="change">
+        this.updateElements();
+      </handler>
+    </handlers>
+  </binding>
+
+  <binding id="prefwindow"
+           extends="chrome://global/content/bindings/dialog.xml#dialog">
+    <resources>
+      <stylesheet src="chrome://global/skin/preferences.css"/>
+    </resources>
+    <content dlgbuttons="accept,cancel" persist="lastSelected screenX screenY"
+             closebuttonlabel="&preferencesCloseButton.label;"
+             closebuttonaccesskey="&preferencesCloseButton.accesskey;"
+             role="dialog"
+#ifdef XP_WIN
+             title="&preferencesDefaultTitleWin.title;">
+#else
+             title="&preferencesDefaultTitleMac.title;">
+#endif
+      <xul:windowdragbox orient="vertical">
+        <xul:radiogroup anonid="selector" orient="horizontal" class="paneSelector chromeclass-toolbar"
+                        role="listbox"/> <!-- Expose to accessibility APIs as a listbox -->
+      </xul:windowdragbox>
+      <xul:hbox flex="1" class="paneDeckContainer">
+        <xul:deck anonid="paneDeck" flex="1">
+          <children includes="prefpane"/>
+        </xul:deck>
+      </xul:hbox>
+      <xul:hbox anonid="dlg-buttons" class="prefWindow-dlgbuttons" pack="end">
+#ifndef XP_UNIX
+        <xul:button dlgtype="disclosure" class="dialog-button" hidden="true"/>
+        <xul:button dlgtype="help" class="dialog-button" hidden="true" icon="help"/>
+        <xul:button dlgtype="extra2" class="dialog-button" hidden="true"/>
+        <xul:button dlgtype="extra1" class="dialog-button" hidden="true"/>
+        <xul:spacer anonid="spacer" flex="1"/>
+        <xul:button dlgtype="cancel" class="dialog-button" icon="cancel"/>
+        <xul:button dlgtype="accept" class="dialog-button" icon="accept"/>
+#else
+        <xul:button dlgtype="extra2" class="dialog-button" hidden="true"/>
+        <xul:spacer anonid="spacer" flex="1"/>
+        <xul:button dlgtype="accept" class="dialog-button" icon="accept"/>
+        <xul:button dlgtype="extra1" class="dialog-button" hidden="true"/>
+        <xul:button dlgtype="cancel" class="dialog-button" icon="cancel"/>
+        <xul:button dlgtype="help" class="dialog-button" hidden="true" icon="help"/>
+        <xul:button dlgtype="disclosure" class="dialog-button" hidden="true"/>
+#endif
+      </xul:hbox>
+      <xul:hbox>
+        <children/>
+      </xul:hbox>
+    </content>
+    <implementation implements="nsITimerCallback">
+      <constructor>
+      <![CDATA[
+        if (this.type != "child") {
+          if (!this._instantApplyInitialized) {
+            let psvc = Components.classes["@mozilla.org/preferences-service;1"]
+                                 .getService(Components.interfaces.nsIPrefBranch);
+            this.instantApply = psvc.getBoolPref("browser.preferences.instantApply");
+          }
+          if (this.instantApply) {
+            var docElt = document.documentElement;
+            var acceptButton = docElt.getButton("accept");
+            acceptButton.hidden = true;
+            var cancelButton  = docElt.getButton("cancel");
+            if (/Mac/.test(navigator.platform)) {
+              // no buttons on Mac except Help
+              cancelButton.hidden = true;
+              // Move Help button to the end
+              document.getAnonymousElementByAttribute(this, "anonid", "spacer").hidden = true;
+              // Also, don't fire onDialogAccept on enter
+              acceptButton.disabled = true;
+            } else {
+              // morph the Cancel button into the Close button
+              cancelButton.setAttribute("icon", "close");
+              cancelButton.label = docElt.getAttribute("closebuttonlabel");
+              cancelButton.accesskey = docElt.getAttribute("closebuttonaccesskey");
+            }
+          }
+        }
+        this.setAttribute("animated", this._shouldAnimate ? "true" : "false");
+        var panes = this.preferencePanes;
+
+        var lastPane = null;
+        if (this.lastSelected) {
+          lastPane = document.getElementById(this.lastSelected);
+          if (!lastPane) {
+            this.lastSelected = "";
+          }
+        }
+
+        var paneToLoad;
+        if ("arguments" in window && window.arguments[0] && document.getElementById(window.arguments[0]) && document.getElementById(window.arguments[0]).nodeName == "prefpane") {
+          paneToLoad = document.getElementById(window.arguments[0]);
+          this.lastSelected = paneToLoad.id;
+        } else if (lastPane)
+          paneToLoad = lastPane;
+        else
+          paneToLoad = panes[0];
+
+        for (var i = 0; i < panes.length; ++i) {
+          this._makePaneButton(panes[i]);
+          if (panes[i].loaded) {
+            // Inline pane content, fire load event to force initialization.
+            this._fireEvent("paneload", panes[i]);
+          }
+        }
+        this.showPane(paneToLoad);
+
+        if (panes.length == 1)
+          this._selector.setAttribute("collapsed", "true");
+      ]]>
+      </constructor>
+
+      <destructor>
+      <![CDATA[
+        // Release timers to avoid reference cycles.
+        if (this._animateTimer) {
+          this._animateTimer.cancel();
+          this._animateTimer = null;
+        }
+        if (this._fadeTimer) {
+          this._fadeTimer.cancel();
+          this._fadeTimer = null;
+        }
+      ]]>
+      </destructor>
+
+      <!-- Derived bindings can set this to true to cause us to skip
+           reading the browser.preferences.instantApply pref in the constructor.
+           Then they can set instantApply to their wished value. -->
+      <field name="_instantApplyInitialized">false</field>
+      <!-- Controls whether changed pref values take effect immediately. -->
+      <field name="instantApply">false</field>
+
+      <property name="preferencePanes"
+                onget="return this.getElementsByTagName('prefpane');"/>
+
+      <property name="type" onget="return this.getAttribute('type');"/>
+      <property name="_paneDeck"
+                onget="return document.getAnonymousElementByAttribute(this, 'anonid', 'paneDeck');"/>
+      <property name="_paneDeckContainer"
+                onget="return document.getAnonymousElementByAttribute(this, 'class', 'paneDeckContainer');"/>
+      <property name="_selector"
+                onget="return document.getAnonymousElementByAttribute(this, 'anonid', 'selector');"/>
+      <property name="lastSelected"
+                onget="return this.getAttribute('lastSelected');">
+        <setter>
+          this.setAttribute("lastSelected", val);
+          document.persist(this.id, "lastSelected");
+          return val;
+        </setter>
+      </property>
+      <property name="currentPane"
+                onset="return this._currentPane = val;">
+        <getter>
+          if (!this._currentPane)
+            this._currentPane = this.preferencePanes[0];
+
+          return this._currentPane;
+        </getter>
+      </property>
+      <field name="_currentPane">null</field>
+
+
+      <method name="_makePaneButton">
+        <parameter name="aPaneElement"/>
+        <body>
+        <![CDATA[
+          var radio = document.createElement("radio");
+          radio.setAttribute("pane", aPaneElement.id);
+          radio.setAttribute("label", aPaneElement.label);
+          // Expose preference group choice to accessibility APIs as an unchecked list item
+          // The parent group is exposed to accessibility APIs as a list
+          if (aPaneElement.image)
+            radio.setAttribute("src", aPaneElement.image);
+          radio.style.listStyleImage = aPaneElement.style.listStyleImage;
+          this._selector.appendChild(radio);
+          return radio;
+        ]]>
+        </body>
+      </method>
+
+      <method name="showPane">
+        <parameter name="aPaneElement"/>
+        <body>
+        <![CDATA[
+          if (!aPaneElement)
+            return;
+
+          this._selector.selectedItem = document.getAnonymousElementByAttribute(this, "pane", aPaneElement.id);
+          if (!aPaneElement.loaded) {
+            let OverlayLoadObserver = function(aPane) {
+              this._pane = aPane;
+            }
+            OverlayLoadObserver.prototype = {
+              _outer: this,
+              observe(aSubject, aTopic, aData) {
+                this._pane.loaded = true;
+                this._outer._fireEvent("paneload", this._pane);
+                this._outer._selectPane(this._pane);
+              }
+            };
+
+            var obs = new OverlayLoadObserver(aPaneElement);
+            document.loadOverlay(aPaneElement.src, obs);
+          } else
+            this._selectPane(aPaneElement);
+        ]]>
+        </body>
+      </method>
+
+      <method name="_fireEvent">
+        <parameter name="aEventName"/>
+        <parameter name="aTarget"/>
+        <body>
+        <![CDATA[
+          // Panel loaded, synthesize a load event.
+          try {
+            var event = document.createEvent("Events");
+            event.initEvent(aEventName, true, true);
+            var cancel = !aTarget.dispatchEvent(event);
+            if (aTarget.hasAttribute("on" + aEventName)) {
+              var fn = new Function("event", aTarget.getAttribute("on" + aEventName));
+              var rv = fn.call(aTarget, event);
+              if (rv == false)
+                cancel = true;
+            }
+            return !cancel;
+          } catch (e) {
+            Components.utils.reportError(e);
+          }
+          return false;
+        ]]>
+        </body>
+      </method>
+
+      <field name="_initialized">false</field>
+      <method name="_selectPane">
+        <parameter name="aPaneElement"/>
+        <body>
+        <![CDATA[
+          if (/Mac/.test(navigator.platform)) {
+            var paneTitle = aPaneElement.label;
+            if (paneTitle != "")
+              document.title = paneTitle;
+          }
+          var helpButton = document.documentElement.getButton("help");
+          if (aPaneElement.helpTopic)
+            helpButton.hidden = false;
+          else
+            helpButton.hidden = true;
+
+          // Find this pane's index in the deck and set the deck's
+          // selectedIndex to that value to switch to it.
+          var prefpanes = this.preferencePanes;
+          for (var i = 0; i < prefpanes.length; ++i) {
+            if (prefpanes[i] == aPaneElement) {
+              this._paneDeck.selectedIndex = i;
+
+              if (this.type != "child") {
+                if (aPaneElement.hasAttribute("flex") && this._shouldAnimate &&
+                    prefpanes.length > 1)
+                  aPaneElement.removeAttribute("flex");
+                // Calling sizeToContent after the first prefpane is loaded
+                // will size the windows contents so style information is
+                // available to calculate correct sizing.
+                if (!this._initialized && prefpanes.length > 1) {
+                  if (this._shouldAnimate)
+                    this.style.minHeight = 0;
+                  window.sizeToContent();
+                }
+
+                var oldPane = this.lastSelected ? document.getElementById(this.lastSelected) : this.preferencePanes[0];
+                oldPane.selected = !(aPaneElement.selected = true);
+                this.lastSelected = aPaneElement.id;
+                this.currentPane = aPaneElement;
+                this._initialized = true;
+
+                // Only animate if we've switched between prefpanes
+                if (this._shouldAnimate && oldPane.id != aPaneElement.id) {
+                  aPaneElement.style.opacity = 0.0;
+                  this.animate(oldPane, aPaneElement);
+                } else if (!this._shouldAnimate && prefpanes.length > 1) {
+                  var targetHeight = parseInt(window.getComputedStyle(this._paneDeckContainer).height);
+                  var verticalPadding = parseInt(window.getComputedStyle(aPaneElement).paddingTop);
+                  verticalPadding += parseInt(window.getComputedStyle(aPaneElement).paddingBottom);
+                  if (aPaneElement.contentHeight > targetHeight - verticalPadding) {
+                    // To workaround the bottom border of a groupbox from being
+                    // cutoff an hbox with a class of bottomBox may enclose it.
+                    // This needs to include its padding to resize properly.
+                    // See bug 394433
+                    var bottomPadding = 0;
+                    var bottomBox = aPaneElement.getElementsByAttribute("class", "bottomBox")[0];
+                    if (bottomBox)
+                      bottomPadding = parseInt(window.getComputedStyle(bottomBox).paddingBottom);
+                    window.innerHeight += bottomPadding + verticalPadding + aPaneElement.contentHeight - targetHeight;
+                  }
+
+                  // XXX rstrong - extend the contents of the prefpane to
+                  // prevent elements from being cutoff (see bug 349098).
+                  if (aPaneElement.contentHeight + verticalPadding < targetHeight)
+                    aPaneElement._content.style.height = targetHeight - verticalPadding + "px";
+                }
+              }
+              break;
+            }
+          }
+        ]]>
+        </body>
+      </method>
+
+      <property name="_shouldAnimate">
+        <getter>
+        <![CDATA[
+          var psvc = Components.classes["@mozilla.org/preferences-service;1"]
+                               .getService(Components.interfaces.nsIPrefBranch);
+          return psvc.getBoolPref("browser.preferences.animateFadeIn",
+                                  /Mac/.test(navigator.platform));
+        ]]>
+        </getter>
+      </property>
+
+      <method name="animate">
+        <parameter name="aOldPane"/>
+        <parameter name="aNewPane"/>
+        <body>
+        <![CDATA[
+          // if we are already resizing, use currentHeight
+          var oldHeight = this._currentHeight ? this._currentHeight : aOldPane.contentHeight;
+
+          this._multiplier = aNewPane.contentHeight > oldHeight ? 1 : -1;
+          var sizeDelta = Math.abs(oldHeight - aNewPane.contentHeight);
+          this._animateRemainder = sizeDelta % this._animateIncrement;
+
+          this._setUpAnimationTimer(oldHeight);
+        ]]>
+        </body>
+      </method>
+
+      <property name="_sizeIncrement">
+        <getter>
+        <![CDATA[
+          var lastSelectedPane = document.getElementById(this.lastSelected);
+          var increment = this._animateIncrement * this._multiplier;
+          var newHeight = this._currentHeight + increment;
+          if ((this._multiplier > 0 && this._currentHeight >= lastSelectedPane.contentHeight) ||
+              (this._multiplier < 0 && this._currentHeight <= lastSelectedPane.contentHeight))
+            return 0;
+
+          if ((this._multiplier > 0 && newHeight > lastSelectedPane.contentHeight) ||
+              (this._multiplier < 0 && newHeight < lastSelectedPane.contentHeight))
+            increment = this._animateRemainder * this._multiplier;
+          return increment;
+        ]]>
+        </getter>
+      </property>
+
+      <method name="notify">
+        <parameter name="aTimer"/>
+        <body>
+        <![CDATA[
+          if (!document)
+            aTimer.cancel();
+
+          if (aTimer == this._animateTimer) {
+            var increment = this._sizeIncrement;
+            if (increment != 0) {
+              window.innerHeight += increment;
+              this._currentHeight += increment;
+            } else {
+              aTimer.cancel();
+              this._setUpFadeTimer();
+            }
+          } else if (aTimer == this._fadeTimer) {
+            var elt = document.getElementById(this.lastSelected);
+            var newOpacity = parseFloat(window.getComputedStyle(elt).opacity) + this._fadeIncrement;
+            if (newOpacity < 1.0)
+              elt.style.opacity = newOpacity;
+            else {
+              aTimer.cancel();
+              elt.style.opacity = 1.0;
+            }
+          }
+        ]]>
+        </body>
+      </method>
+
+      <method name="_setUpAnimationTimer">
+        <parameter name="aStartHeight"/>
+        <body>
+        <![CDATA[
+          if (!this._animateTimer)
+            this._animateTimer = Components.classes["@mozilla.org/timer;1"]
+                                           .createInstance(Components.interfaces.nsITimer);
+          else
+            this._animateTimer.cancel();
+          this._currentHeight = aStartHeight;
+
+          this._animateTimer.initWithCallback(this, this._animateDelay,
+                                              Components.interfaces.nsITimer.TYPE_REPEATING_SLACK);
+        ]]>
+        </body>
+      </method>
+
+      <method name="_setUpFadeTimer">
+        <body>
+        <![CDATA[
+          if (!this._fadeTimer)
+            this._fadeTimer = Components.classes["@mozilla.org/timer;1"]
+                                        .createInstance(Components.interfaces.nsITimer);
+          else
+            this._fadeTimer.cancel();
+
+          this._fadeTimer.initWithCallback(this, this._fadeDelay,
+                                           Components.interfaces.nsITimer.TYPE_REPEATING_SLACK);
+        ]]>
+        </body>
+      </method>
+
+      <field name="_animateTimer">null</field>
+      <field name="_fadeTimer">null</field>
+      <field name="_animateDelay">15</field>
+      <field name="_animateIncrement">40</field>
+      <field name="_fadeDelay">5</field>
+      <field name="_fadeIncrement">0.40</field>
+      <field name="_animateRemainder">0</field>
+      <field name="_currentHeight">0</field>
+      <field name="_multiplier">0</field>
+
+      <method name="addPane">
+        <parameter name="aPaneElement"/>
+        <body>
+        <![CDATA[
+          this.appendChild(aPaneElement);
+
+          // Set up pane button
+          this._makePaneButton(aPaneElement);
+        ]]>
+        </body>
+      </method>
+
+      <method name="openSubDialog">
+        <parameter name="aURL"/>
+        <parameter name="aFeatures"/>
+        <parameter name="aParams"/>
+        <body>
+          return openDialog(aURL, "", "modal,centerscreen,resizable=no" + (aFeatures != "" ? ("," + aFeatures) : ""), aParams);
+        </body>
+      </method>
+
+      <method name="openWindow">
+        <parameter name="aWindowType"/>
+        <parameter name="aURL"/>
+        <parameter name="aFeatures"/>
+        <parameter name="aParams"/>
+        <body>
+        <![CDATA[
+          var wm = Components.classes["@mozilla.org/appshell/window-mediator;1"]
+                             .getService(Components.interfaces.nsIWindowMediator);
+          var win = aWindowType ? wm.getMostRecentWindow(aWindowType) : null;
+          if (win) {
+            if ("initWithParams" in win)
+              win.initWithParams(aParams);
+            win.focus();
+          } else {
+            var features = "resizable,dialog=no,centerscreen" + (aFeatures != "" ? ("," + aFeatures) : "");
+            var parentWindow = (this.instantApply || !window.opener || window.opener.closed) ? window : window.opener;
+            win = parentWindow.openDialog(aURL, "_blank", features, aParams);
+          }
+          return win;
+        ]]>
+        </body>
+      </method>
+    </implementation>
+    <handlers>
+      <handler event="dialogaccept">
+      <![CDATA[
+        if (!this._fireEvent("beforeaccept", this)) {
+          return false;
+        }
+
+        var secMan = Components.classes["@mozilla.org/scriptsecuritymanager;1"]
+                    .getService(Components.interfaces.nsIScriptSecurityManager);
+        if (this.type == "child" && window.opener &&
+            secMan.isSystemPrincipal(window.opener.document.nodePrincipal)) {
+          var pdocEl = window.opener.document.documentElement;
+          if (pdocEl.instantApply) {
+            let panes = this.preferencePanes;
+            for (let i = 0; i < panes.length; ++i)
+              panes[i].writePreferences(true);
+          } else {
+            // Clone all the preferences elements from the child document and
+            // insert them into the pane collection of the parent.
+            var pdoc = window.opener.document;
+            if (pdoc.documentElement.localName == "prefwindow") {
+              var currentPane = pdoc.documentElement.currentPane;
+              var id = window.location.href + "#childprefs";
+              var childPrefs = pdoc.getElementById(id);
+              if (!childPrefs) {
+                childPrefs = pdoc.createElement("preferences");
+                currentPane.appendChild(childPrefs);
+                childPrefs.id = id;
+              }
+              let panes = this.preferencePanes;
+              for (let i = 0; i < panes.length; ++i) {
+                var preferences = panes[i].preferences;
+                for (var j = 0; j < preferences.length; ++j) {
+                  // Try to find a preference element for the same preference.
+                  var preference = null;
+                  var parentPreferences = pdoc.getElementsByTagName("preferences");
+                  for (var k = 0; (k < parentPreferences.length && !preference); ++k) {
+                    var parentPrefs = parentPreferences[k]
+                                         .getElementsByAttribute("name", preferences[j].name);
+                    for (var l = 0; (l < parentPrefs.length && !preference); ++l) {
+                      if (parentPrefs[l].localName == "preference")
+                        preference = parentPrefs[l];
+                    }
+                  }
+                  if (!preference) {
+                    // No matching preference in the parent window.
+                    preference = pdoc.createElement("preference");
+                    childPrefs.appendChild(preference);
+                    preference.name     = preferences[j].name;
+                    preference.type     = preferences[j].type;
+                    preference.inverted = preferences[j].inverted;
+                    preference.readonly = preferences[j].readonly;
+                    preference.disabled = preferences[j].disabled;
+                  }
+                  preference.value = preferences[j].value;
+                }
+              }
+            }
+          }
+        } else {
+          let panes = this.preferencePanes;
+          for (var i = 0; i < panes.length; ++i)
+            panes[i].writePreferences(false);
+
+          let psvc = Components.classes["@mozilla.org/preferences-service;1"]
+                               .getService(Components.interfaces.nsIPrefService);
+          psvc.savePrefFile(null);
+        }
+
+        return true;
+      ]]>
+      </handler>
+      <handler event="command">
+        if (event.originalTarget.hasAttribute("pane")) {
+          var pane = document.getElementById(event.originalTarget.getAttribute("pane"));
+          this.showPane(pane);
+        }
+      </handler>
+
+      <handler event="keypress" key="&windowClose.key;" modifiers="accel" phase="capturing">
+      <![CDATA[
+        if (this.instantApply)
+          window.close();
+        event.stopPropagation();
+        event.preventDefault();
+      ]]>
+      </handler>
+
+      <handler event="keypress"
+#ifdef XP_MACOSX
+               key="&openHelpMac.commandkey;" modifiers="accel"
+#else
+               keycode="&openHelp.commandkey;"
+#endif
+               phase="capturing">
+      <![CDATA[
+        var helpButton = this.getButton("help");
+        if (helpButton.disabled || helpButton.hidden)
+          return;
+        this._fireEvent("dialoghelp", this);
+        event.stopPropagation();
+        event.preventDefault();
+      ]]>
+      </handler>
+    </handlers>
+  </binding>
+
+  <binding id="prefpane">
+    <resources>
+      <stylesheet src="chrome://global/skin/preferences.css"/>
+    </resources>
+    <content>
+      <xul:vbox class="content-box" xbl:inherits="flex">
+        <children/>
+      </xul:vbox>
+    </content>
+    <implementation>
+      <method name="writePreferences">
+        <parameter name="aFlushToDisk"/>
+        <body>
+        <![CDATA[
+          // Write all values to preferences.
+          if (this._deferredValueUpdateElements.size) {
+            this._finalizeDeferredElements();
+          }
+
+          var preferences = this.preferences;
+          for (var i = 0; i < preferences.length; ++i) {
+            var preference = preferences[i];
+            preference.batching = true;
+            preference.valueFromPreferences = preference.value;
+            preference.batching = false;
+          }
+          if (aFlushToDisk) {
+            var psvc = Components.classes["@mozilla.org/preferences-service;1"]
+                                 .getService(Components.interfaces.nsIPrefService);
+            psvc.savePrefFile(null);
+          }
+        ]]>
+        </body>
+      </method>
+
+      <property name="src"
+                onget="return this.getAttribute('src');"
+                onset="this.setAttribute('src', val); return val;"/>
+      <property name="selected"
+                onget="return this.getAttribute('selected') == 'true';"
+                onset="this.setAttribute('selected', val); return val;"/>
+      <property name="image"
+                onget="return this.getAttribute('image');"
+                onset="this.setAttribute('image', val); return val;"/>
+      <property name="label"
+                onget="return this.getAttribute('label');"
+                onset="this.setAttribute('label', val); return val;"/>
+
+      <property name="preferenceElements"
+                onget="return this.getElementsByAttribute('preference', '*');"/>
+      <property name="preferences"
+                onget="return this.getElementsByTagName('preference');"/>
+
+      <property name="helpTopic">
+        <getter>
+        <![CDATA[
+          // if there are tabs, and the selected tab provides a helpTopic, return that
+          var box = this.getElementsByTagName("tabbox");
+          if (box[0]) {
+            var tab = box[0].selectedTab;
+            if (tab && tab.hasAttribute("helpTopic"))
+              return tab.getAttribute("helpTopic");
+          }
+
+          // otherwise, return the helpTopic of the current panel
+          return this.getAttribute("helpTopic");
+        ]]>
+        </getter>
+      </property>
+
+      <field name="_loaded">false</field>
+      <property name="loaded"
+                onget="return !this.src ? true : this._loaded;"
+                onset="this._loaded = val; return val;"/>
+
+      <method name="preferenceForElement">
+        <parameter name="aElement"/>
+        <body>
+          return document.getElementById(aElement.getAttribute("preference"));
+        </body>
+      </method>
+
+      <method name="getPreferenceElement">
+        <parameter name="aStartElement"/>
+        <body>
+        <![CDATA[
+          var temp = aStartElement;
+          while (temp && temp.nodeType == Node.ELEMENT_NODE &&
+                 !temp.hasAttribute("preference"))
+            temp = temp.parentNode;
+          return temp && temp.nodeType == Node.ELEMENT_NODE ?
+                 temp : aStartElement;
+        ]]>
+        </body>
+      </method>
+
+      <property name="DeferredTask" readonly="true">
+        <getter><![CDATA[
+          let module = {};
+          Components.utils.import("resource://gre/modules/DeferredTask.jsm", module);
+          Object.defineProperty(this, "DeferredTask", {
+            configurable: true,
+            enumerable: true,
+            writable: true,
+            value: module.DeferredTask
+          });
+          return module.DeferredTask;
+        ]]></getter>
+      </property>
+      <method name="_deferredValueUpdate">
+        <parameter name="aElement"/>
+        <body>
+        <![CDATA[
+          delete aElement._deferredValueUpdateTask;
+          let preference = document.getElementById(aElement.getAttribute("preference"));
+          let prefVal = preference.getElementValue(aElement);
+          preference.value = prefVal;
+          this._deferredValueUpdateElements.delete(aElement);
+        ]]>
+        </body>
+      </method>
+      <field name="_deferredValueUpdateElements">
+        new Set();
+      </field>
+      <method name="_finalizeDeferredElements">
+        <body>
+        <![CDATA[
+          for (let el of this._deferredValueUpdateElements) {
+            if (el._deferredValueUpdateTask) {
+              el._deferredValueUpdateTask.finalize();
+            }
+          }
+        ]]>
+        </body>
+      </method>
+      <method name="userChangedValue">
+        <parameter name="aElement"/>
+        <body>
+        <![CDATA[
+          let element = this.getPreferenceElement(aElement);
+          if (element.hasAttribute("preference")) {
+            if (element.getAttribute("delayprefsave") != "true") {
+              var preference = document.getElementById(element.getAttribute("preference"));
+              var prefVal = preference.getElementValue(element);
+              preference.value = prefVal;
+            } else {
+              if (!element._deferredValueUpdateTask) {
+                element._deferredValueUpdateTask = new this.DeferredTask(this._deferredValueUpdate.bind(this, element), 1000);
+                this._deferredValueUpdateElements.add(element);
+              } else {
+                // Each time the preference is changed, restart the delay.
+                element._deferredValueUpdateTask.disarm();
+              }
+              element._deferredValueUpdateTask.arm();
+            }
+          }
+        ]]>
+        </body>
+      </method>
+
+      <property name="contentHeight">
+        <getter>
+          var targetHeight = parseInt(window.getComputedStyle(this._content).height);
+          targetHeight += parseInt(window.getComputedStyle(this._content).marginTop);
+          targetHeight += parseInt(window.getComputedStyle(this._content).marginBottom);
+          return targetHeight;
+        </getter>
+      </property>
+      <field name="_content">
+        document.getAnonymousElementByAttribute(this, "class", "content-box");
+      </field>
+    </implementation>
+    <handlers>
+      <handler event="command">
+        // This "command" event handler tracks changes made to preferences by
+        // the user in this window.
+        if (event.sourceEvent)
+          event = event.sourceEvent;
+        this.userChangedValue(event.target);
+      </handler>
+      <handler event="select">
+        // This "select" event handler tracks changes made to colorpicker
+        // preferences by the user in this window.
+        if (event.target.localName == "colorpicker")
+          this.userChangedValue(event.target);
+      </handler>
+      <handler event="change">
+        // This "change" event handler tracks changes made to preferences by
+        // the user in this window.
+        this.userChangedValue(event.target);
+      </handler>
+      <handler event="input">
+        // This "input" event handler tracks changes made to preferences by
+        // the user in this window.
+        this.userChangedValue(event.target);
+      </handler>
+      <handler event="paneload">
+      <![CDATA[
+        // Initialize all values from preferences.
+        var elements = this.preferenceElements;
+        for (var i = 0; i < elements.length; ++i) {
+          try {
+            var preference = this.preferenceForElement(elements[i]);
+            preference.setElementValue(elements[i]);
+          } catch (e) {
+            dump("*** No preference found for " + elements[i].getAttribute("preference") + "\n");
+          }
+        }
+      ]]>
+      </handler>
+    </handlers>
+  </binding>
+
+  <binding id="panebutton" role="xul:listitem"
+           extends="chrome://global/content/bindings/radio.xml#radio">
+    <resources>
+      <stylesheet src="chrome://global/skin/preferences.css"/>
+    </resources>
+    <content>
+      <xul:image class="paneButtonIcon" xbl:inherits="src"/>
+      <xul:label class="paneButtonLabel" xbl:inherits="value=label"/>
+    </content>
+  </binding>
+
+</bindings>
+
+# -*- Mode: Java; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*-
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+#
+# This is PrefWindow 6. The Code Could Well Be Ready, Are You?
+#
+#    Historical References:
+#    PrefWindow V   (February 1, 2003)
+#    PrefWindow IV  (April 24, 2000)
+#    PrefWindow III (January 6, 2000)
+#    PrefWindow II  (???)
+#    PrefWindow I   (June 4, 1999)
+#
diff --git a/toolkit/mozapps/downloads/nsHelperAppDlg.js b/toolkit/mozapps/downloads/nsHelperAppDlg.js
--- a/toolkit/mozapps/downloads/nsHelperAppDlg.js
+++ b/toolkit/mozapps/downloads/nsHelperAppDlg.js
@@ -626,17 +626,17 @@ nsUnknownContentTypeDialog.prototype = {
       else
         typeString = mimeInfo.MIMEType;
     }
     // When the length is unknown, contentLength would be -1
     if (this.mLauncher.contentLength >= 0) {
       let [size, unit] = DownloadUtils.
                          convertByteUnits(this.mLauncher.contentLength);
       type.value = this.dialogElement("strings")
-                       .getFormattedString("orderedFileSizeWithType", 
+                       .getFormattedString("orderedFileSizeWithType",
                                            [typeString, size, unit]);
     }
     else {
       type.value = typeString;
     }
   },
 
   // Returns true if opening the default application makes sense.
@@ -800,17 +800,17 @@ nsUnknownContentTypeDialog.prototype = {
       switch (this.dialogElement("openHandler").selectedIndex) {
       case 0:
         // No app need be specified in this case.
         ok = true;
         break;
       case 1:
         // only enable the OK button if we have a default app to use or if
         // the user chose an app....
-        ok = this.chosenApp || /\S/.test(this.dialogElement("otherHandler").getAttribute("path")); 
+        ok = this.chosenApp || /\S/.test(this.dialogElement("otherHandler").getAttribute("path"));
         break;
       }
     }
 
     // Enable Ok button if ok to press.
     this.mDialog.document.documentElement.getButton("accept").disabled = !ok;
   },
 
@@ -1065,30 +1065,57 @@ nsUnknownContentTypeDialog.prototype = {
 
       if (params.handlerApp &&
           params.handlerApp.executable &&
           params.handlerApp.executable.isFile()) {
         // Remember the file they chose to run.
         this.chosenApp = params.handlerApp;
       }
     } else if ("@mozilla.org/applicationchooser;1" in Components.classes) {
-      var nsIApplicationChooser = Components.interfaces.nsIApplicationChooser;
-      var appChooser = Components.classes["@mozilla.org/applicationchooser;1"]
-                                 .createInstance(nsIApplicationChooser);
-      appChooser.init(this.mDialog, this.dialogElement("strings").getString("chooseAppFilePickerTitle"));
-      var contentTypeDialogObj = this;
-      let appChooserCallback = function appChooserCallback_done(aResult) {
-        if (aResult) {
-           contentTypeDialogObj.chosenApp = aResult.QueryInterface(Components.interfaces.nsILocalHandlerApp);
+      // handle the KDE case which is implemented in the filepicker
+      // therefore falling back to Gtk2 like behaviour if KDE is running
+      // FIXME this should be better handled in the nsIApplicationChooser
+      // interface
+      var env = Components.classes["@mozilla.org/process/environment;1"]
+                          .getService(Components.interfaces.nsIEnvironment);
+      if (env.get('KDE_FULL_SESSION') == "true")
+      {
+        var nsIFilePicker = Components.interfaces.nsIFilePicker;
+        var fp = Components.classes["@mozilla.org/filepicker;1"]
+                           .createInstance(nsIFilePicker);
+        fp.init(this.mDialog,
+                this.dialogElement("strings").getString("chooseAppFilePickerTitle"),
+                nsIFilePicker.modeOpen);
+
+        fp.appendFilters(nsIFilePicker.filterApps);
+
+        if (fp.show() == nsIFilePicker.returnOK && fp.file) {
+          // Remember the file they chose to run.
+          var localHandlerApp =
+            Components.classes["@mozilla.org/uriloader/local-handler-app;1"].
+                       createInstance(Components.interfaces.nsILocalHandlerApp);
+          localHandlerApp.executable = fp.file;
+          this.chosenApp = localHandlerApp;
         }
-        contentTypeDialogObj.finishChooseApp();
-      };
-      appChooser.open(this.mLauncher.MIMEInfo.MIMEType, appChooserCallback);
-      // The finishChooseApp is called from appChooserCallback
-      return;
+      } else {
+        var nsIApplicationChooser = Components.interfaces.nsIApplicationChooser;
+        var appChooser = Components.classes["@mozilla.org/applicationchooser;1"]
+                                   .createInstance(nsIApplicationChooser);
+        appChooser.init(this.mDialog, this.dialogElement("strings").getString("chooseAppFilePickerTitle"));
+        var contentTypeDialogObj = this;
+        let appChooserCallback = function appChooserCallback_done(aResult) {
+          if (aResult) {
+             contentTypeDialogObj.chosenApp = aResult.QueryInterface(Components.interfaces.nsILocalHandlerApp);
+          }
+          contentTypeDialogObj.finishChooseApp();
+        };
+        appChooser.open(this.mLauncher.MIMEInfo.MIMEType, appChooserCallback);
+        // The finishChooseApp is called from appChooserCallback
+        return;
+      }
     } else {
       var nsIFilePicker = Components.interfaces.nsIFilePicker;
       var fp = Components.classes["@mozilla.org/filepicker;1"]
                          .createInstance(nsIFilePicker);
       fp.init(this.mDialog,
               this.dialogElement("strings").getString("chooseAppFilePickerTitle"),
               nsIFilePicker.modeOpen);
 
diff --git a/toolkit/system/unixproxy/nsUnixSystemProxySettings.cpp b/toolkit/system/unixproxy/nsUnixSystemProxySettings.cpp
--- a/toolkit/system/unixproxy/nsUnixSystemProxySettings.cpp
+++ b/toolkit/system/unixproxy/nsUnixSystemProxySettings.cpp
@@ -15,16 +15,17 @@
 #include "nsPrintfCString.h"
 #include "nsNetCID.h"
 #include "nsNetUtil.h"
 #include "nsISupportsPrimitives.h"
 #include "nsIGSettingsService.h"
 #include "nsInterfaceHashtable.h"
 #include "mozilla/Attributes.h"
 #include "nsIURI.h"
+#include "nsKDEUtils.h"
 
 class nsUnixSystemProxySettings final : public nsISystemProxySettings {
 public:
   NS_DECL_ISUPPORTS
   NS_DECL_NSISYSTEMPROXYSETTINGS
 
   nsUnixSystemProxySettings()
     : mSchemeProxySettings(4)
@@ -39,16 +40,17 @@ private:
   nsCOMPtr<nsIGSettingsService> mGSettings;
   nsCOMPtr<nsIGSettingsCollection> mProxySettings;
   nsInterfaceHashtable<nsCStringHashKey, nsIGSettingsCollection> mSchemeProxySettings;
   bool IsProxyMode(const char* aMode);
   nsresult SetProxyResultFromGConf(const char* aKeyBase, const char* aType, nsACString& aResult);
   nsresult GetProxyFromGConf(const nsACString& aScheme, const nsACString& aHost, int32_t aPort, nsACString& aResult);
   nsresult GetProxyFromGSettings(const nsACString& aScheme, const nsACString& aHost, int32_t aPort, nsACString& aResult);
   nsresult SetProxyResultFromGSettings(const char* aKeyBase, const char* aType, nsACString& aResult);
+  nsresult GetProxyFromKDE(const nsACString& aScheme, const nsACString& aHost, PRInt32 aPort, nsACString& aResult);
 };
 
 NS_IMPL_ISUPPORTS(nsUnixSystemProxySettings, nsISystemProxySettings)
 
 NS_IMETHODIMP
 nsUnixSystemProxySettings::GetMainThreadOnly(bool *aMainThreadOnly)
 {
   // dbus prevents us from being threadsafe, but this routine should not block anyhow
@@ -505,16 +507,19 @@ nsUnixSystemProxySettings::GetProxyFromG
 
 nsresult
 nsUnixSystemProxySettings::GetProxyForURI(const nsACString & aSpec,
                                           const nsACString & aScheme,
                                           const nsACString & aHost,
                                           const int32_t      aPort,
                                           nsACString & aResult)
 {
+  if (nsKDEUtils::kdeSupport())
+    return GetProxyFromKDE(aScheme, aHost, aPort, aResult);
+
   if (mProxySettings) {
     nsresult rv = GetProxyFromGSettings(aScheme, aHost, aPort, aResult);
     if (NS_SUCCEEDED(rv))
       return rv;
   }
   if (mGConf)
     return GetProxyFromGConf(aScheme, aHost, aPort, aResult);
 
@@ -540,8 +545,34 @@ static const mozilla::Module::ContractID
 
 static const mozilla::Module kUnixProxyModule = {
   mozilla::Module::kVersion,
   kUnixProxyCIDs,
   kUnixProxyContracts
 };
 
 NSMODULE_DEFN(nsUnixProxyModule) = &kUnixProxyModule;
+
+nsresult
+nsUnixSystemProxySettings::GetProxyFromKDE(const nsACString& aScheme,
+                                           const nsACString& aHost,
+                                           PRInt32 aPort,
+                                           nsACString& aResult)
+{
+  nsAutoCString url;
+  url = aScheme;
+  url += "://";
+  url += aHost;
+  if( aPort >= 0 )
+  {
+    url += ":";
+    url += nsPrintfCString("%d", aPort);
+  }
+  nsTArray<nsCString> command;
+  command.AppendElement( NS_LITERAL_CSTRING( "GETPROXY" ));
+  command.AppendElement( url );
+  nsTArray<nsCString> result;
+  if( !nsKDEUtils::command( command, &result ) || result.Length() != 1 )
+    return NS_ERROR_FAILURE;
+  aResult = result[0];
+  return NS_OK;
+}
+
diff --git a/toolkit/xre/moz.build b/toolkit/xre/moz.build
--- a/toolkit/xre/moz.build
+++ b/toolkit/xre/moz.build
@@ -61,17 +61,19 @@ elif CONFIG['MOZ_WIDGET_TOOLKIT'] == 'co
         '../components/printingui/mac',
     ]
 elif CONFIG['MOZ_WIDGET_TOOLKIT'] == 'uikit':
     UNIFIED_SOURCES += [
         'nsNativeAppSupportDefault.cpp',
         'UIKitDirProvider.mm',
     ]
 elif 'gtk' in CONFIG['MOZ_WIDGET_TOOLKIT']:
+    EXPORTS += ['nsKDEUtils.h']
     UNIFIED_SOURCES += [
+        'nsKDEUtils.cpp',
         'nsNativeAppSupportUnix.cpp',
     ]
 else:
     UNIFIED_SOURCES += [
         'nsNativeAppSupportDefault.cpp',
     ]
 
 if CONFIG['MOZ_WIDGET_TOOLKIT'] == 'gtk3':
diff --git a/toolkit/xre/nsKDEUtils.cpp b/toolkit/xre/nsKDEUtils.cpp
new file mode 100644
--- /dev/null
+++ b/toolkit/xre/nsKDEUtils.cpp
@@ -0,0 +1,344 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsKDEUtils.h"
+#include "nsIWidget.h"
+#include "nsISupportsPrimitives.h"
+#include "nsIMutableArray.h"
+#include "nsComponentManagerUtils.h"
+#include "nsArrayUtils.h"
+
+#include <gtk/gtk.h>
+
+#include <limits.h>
+#include <stdio.h>
+#include <sys/wait.h>
+#include <sys/resource.h>
+#include <unistd.h>
+#include <X11/Xlib.h>
+// copied from X11/X.h as a hack since for an unknown
+// reason it's not picked up from X11/X.h
+#ifndef None
+#define None                 0L /* universal null resource or null atom */
+#endif
+
+//#define DEBUG_KDE
+#ifdef DEBUG_KDE
+#define KMOZILLAHELPER "kmozillahelper"
+#else
+// not need for lib64, it's a binary
+#define KMOZILLAHELPER "/usr/lib/mozilla/kmozillahelper"
+#endif
+
+#define KMOZILLAHELPER_VERSION 6
+#define MAKE_STR2( n ) #n
+#define MAKE_STR( n ) MAKE_STR2( n )
+
+static bool getKdeSession()
+    {
+    Display* dpy = XOpenDisplay( NULL );
+    if( dpy == NULL )
+        return false;
+    Atom kde_full_session = XInternAtom( dpy, "KDE_FULL_SESSION", True );
+    bool kde = false;
+    if( kde_full_session != None )
+        {
+        int cnt;
+        if( Atom* props = XListProperties( dpy, DefaultRootWindow( dpy ), &cnt ))
+            {
+            for( int i = 0;
+                 i < cnt;
+                 ++i )
+                {
+                if( props[ i ] == kde_full_session )
+                    {
+                    kde = true;
+#ifdef DEBUG_KDE
+                    fprintf( stderr, "KDE SESSION %d\n", kde );
+#endif
+                    break;
+                    }
+                }
+            XFree( props );
+            }
+        }
+    XCloseDisplay( dpy );
+    return kde;
+    }
+
+static bool getKdeSupport()
+    {
+    nsTArray<nsCString> command;
+    command.AppendElement( NS_LITERAL_CSTRING( "CHECK" ));
+    command.AppendElement( NS_LITERAL_CSTRING( MAKE_STR( KMOZILLAHELPER_VERSION )));
+    bool kde = nsKDEUtils::command( command );
+#ifdef DEBUG_KDE
+    fprintf( stderr, "KDE RUNNING %d\n", kde );
+#endif
+    return kde;
+    }
+
+nsKDEUtils::nsKDEUtils()
+    : commandFile( NULL )
+    , replyFile( NULL )
+    {
+    }
+
+nsKDEUtils::~nsKDEUtils()
+    {
+//    closeHelper(); not actually useful, exiting will close the fd too
+    }
+
+nsKDEUtils* nsKDEUtils::self()
+    {
+    static nsKDEUtils s;
+    return &s;
+    }
+
+static bool helperRunning = false;
+static bool helperFailed = false;
+
+bool nsKDEUtils::kdeSession()
+    {
+    static bool session = getKdeSession();
+    return session;
+    }
+
+bool nsKDEUtils::kdeSupport()
+    {
+    static bool support = kdeSession() && getKdeSupport();
+    return support && helperRunning;
+    }
+
+struct nsKDECommandData
+    {
+    FILE* file;
+    nsTArray<nsCString>* output;
+    GMainLoop* loop;
+    bool success;
+    };
+
+static gboolean kdeReadFunc( GIOChannel*, GIOCondition, gpointer data )
+    {
+    nsKDECommandData* p = static_cast< nsKDECommandData* >( data );
+    char buf[ 8192 ]; // TODO big enough
+    bool command_done = false;
+    bool command_failed = false;
+    while( !command_done && !command_failed && fgets( buf, 8192, p->file ) != NULL )
+        { // TODO what if the kernel splits a line into two chunks?
+//#ifdef DEBUG_KDE
+//        fprintf( stderr, "READ: %s %d\n", buf, feof( p->file ));
+//#endif
+        if( char* eol = strchr( buf, '\n' ))
+            *eol = '\0';
+        command_done = ( strcmp( buf, "\\1" ) == 0 );
+        command_failed = ( strcmp( buf, "\\0" ) == 0 );
+        nsAutoCString line( buf );
+        line.ReplaceSubstring( "\\n", "\n" );
+        line.ReplaceSubstring( "\\" "\\", "\\" ); //  \\ -> \ , i.e. unescape
+        if( p->output && !( command_done || command_failed ))
+            p->output->AppendElement( nsCString( buf )); // TODO utf8?
+        }
+    bool quit = false;
+    if( feof( p->file ) || command_failed )
+        {
+        quit = true;
+        p->success = false;
+        }
+    if( command_done )
+        { // reading one reply finished
+        quit = true;
+        p->success = true;
+        }
+    if( quit )
+        {
+        if( p->loop )
+            g_main_loop_quit( p->loop );
+        return FALSE;
+        }
+    return TRUE;
+    }
+
+bool nsKDEUtils::command( const nsTArray<nsCString>& command, nsTArray<nsCString>* output )
+    {
+    return self()->internalCommand( command, NULL, false, output );
+    }
+
+bool nsKDEUtils::command( nsIArray* command, nsIArray** output)
+    {
+    nsTArray<nsCString> in;
+    PRUint32 length;
+    command->GetLength( &length );
+    for ( PRUint32 i = 0; i < length; i++ )
+        {
+        nsCOMPtr<nsISupportsCString> str = do_QueryElementAt( command, i );
+        if( str )
+            {
+            nsAutoCString s;
+            str->GetData( s );
+            in.AppendElement( s );
+            }
+        }
+
+    nsTArray<nsCString> out;
+    bool ret = self()->internalCommand( in, NULL, false, &out );
+
+    if ( !output ) return ret;
+
+    nsCOMPtr<nsIMutableArray> result = do_CreateInstance( NS_ARRAY_CONTRACTID );
+    if ( !result ) return false;
+
+    for ( PRUint32 i = 0; i < out.Length(); i++ )
+        {
+        nsCOMPtr<nsISupportsCString> rstr = do_CreateInstance( NS_SUPPORTS_CSTRING_CONTRACTID );
+        if ( !rstr ) return false;
+
+        rstr->SetData( out[i] );
+        result->AppendElement( rstr );
+        }
+
+    NS_ADDREF( *output = result);
+    return ret;
+    }
+
+
+bool nsKDEUtils::commandBlockUi( const nsTArray<nsCString>& command, GtkWindow* parent, nsTArray<nsCString>* output )
+    {
+    return self()->internalCommand( command, parent, true, output );
+    }
+
+bool nsKDEUtils::internalCommand( const nsTArray<nsCString>& command, GtkWindow* parent, bool blockUi,
+    nsTArray<nsCString>* output )
+    {
+    if( !startHelper())
+        return false;
+    feedCommand( command );
+    // do not store the data in 'this' but in extra structure, just in case there
+    // is reentrancy (can there be? the event loop is re-entered)
+    nsKDECommandData data;
+    data.file = replyFile;
+    data.output = output;
+    data.success = false;
+    if( blockUi )
+        {
+        data.loop = g_main_loop_new( NULL, FALSE );
+        GtkWidget* window = gtk_window_new( GTK_WINDOW_TOPLEVEL );
+        if( parent && gtk_window_get_group(parent) )
+            gtk_window_group_add_window( gtk_window_get_group(parent), GTK_WINDOW( window ));
+        gtk_widget_realize( window );
+        gtk_widget_set_sensitive( window, TRUE );
+        gtk_grab_add( window );
+        GIOChannel* channel = g_io_channel_unix_new( fileno( data.file ));
+        g_io_add_watch( channel, static_cast< GIOCondition >( G_IO_IN | G_IO_ERR | G_IO_HUP ), kdeReadFunc, &data );
+        g_io_channel_unref( channel );
+        g_main_loop_run( data.loop );
+        g_main_loop_unref( data.loop );
+        gtk_grab_remove( window );
+        gtk_widget_destroy( window );
+        }
+    else
+        {
+        data.loop = NULL;
+        while( kdeReadFunc( NULL, static_cast< GIOCondition >( 0 ), &data ))
+            ;
+        }
+    return data.success;
+    }
+
+bool nsKDEUtils::startHelper()
+    {
+    if( helperRunning )
+        return true;
+    if( helperFailed )
+        return false;
+    helperFailed = true;
+    int fdcommand[ 2 ];
+    int fdreply[ 2 ];
+    if( pipe( fdcommand ) < 0 )
+        return false;
+    if( pipe( fdreply ) < 0 )
+        {
+        close( fdcommand[ 0 ] );
+        close( fdcommand[ 1 ] );
+        return false;
+        }
+    char* args[ 2 ] = { const_cast< char* >( KMOZILLAHELPER ), NULL };
+    switch( fork())
+        {
+        case -1:
+            {
+            close( fdcommand[ 0 ] );
+            close( fdcommand[ 1 ] );
+            close( fdreply[ 0 ] );
+            close( fdreply[ 1 ] );
+            return false;
+            }
+        case 0: // child
+            {
+            if( dup2( fdcommand[ 0 ], STDIN_FILENO ) < 0 )
+                _exit( 1 );
+            if( dup2( fdreply[ 1 ], STDOUT_FILENO ) < 0 )
+                _exit( 1 );
+            int maxfd = 1024; // close all other fds
+            struct rlimit rl;
+            if( getrlimit( RLIMIT_NOFILE, &rl ) == 0 )
+                maxfd = rl.rlim_max;
+            for( int i = 3;
+                 i < maxfd;
+                 ++i )
+                close( i );
+#ifdef DEBUG_KDE
+            execvp( KMOZILLAHELPER, args );
+#else
+            execv( KMOZILLAHELPER, args );
+#endif
+            _exit( 1 ); // failed
+            }
+        default: // parent
+            {
+            commandFile = fdopen( fdcommand[ 1 ], "w" );
+            replyFile = fdopen( fdreply[ 0 ], "r" );
+            close( fdcommand[ 0 ] );
+            close( fdreply[ 1 ] );
+            if( commandFile == NULL || replyFile == NULL )
+                {
+                closeHelper();
+                return false;
+                }
+            // ok, helper ready, getKdeRunning() will check if it works
+            }
+        }
+    helperFailed = false;
+    helperRunning = true;
+    return true;
+    }
+
+void nsKDEUtils::closeHelper()
+    {
+    if( commandFile != NULL )
+        fclose( commandFile ); // this will also make the helper quit
+    if( replyFile != NULL )
+        fclose( replyFile );
+    helperRunning = false;
+    }
+
+void nsKDEUtils::feedCommand( const nsTArray<nsCString>& command )
+    {
+    for( int i = 0;
+         i < command.Length();
+         ++i )
+        {
+        nsCString line = command[ i ];
+        line.ReplaceSubstring( "\\", "\\" "\\" ); // \ -> \\ , i.e. escape
+        line.ReplaceSubstring( "\n", "\\n" );
+#ifdef DEBUG_KDE
+        fprintf( stderr, "COMM: %s\n", line.get());
+#endif
+        fputs( line.get(), commandFile );
+        fputs( "\n", commandFile );
+        }
+    fputs( "\\E\n", commandFile ); // done as \E, so it cannot happen in normal data
+    fflush( commandFile );
+    }
diff --git a/toolkit/xre/nsKDEUtils.h b/toolkit/xre/nsKDEUtils.h
new file mode 100644
--- /dev/null
+++ b/toolkit/xre/nsKDEUtils.h
@@ -0,0 +1,48 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef nsKDEUtils_h__
+#define nsKDEUtils_h__
+
+#include "nsStringGlue.h"
+#include "nsTArray.h"
+#include <stdio.h>
+
+typedef struct _GtkWindow GtkWindow;
+
+class nsIArray;
+
+class NS_EXPORT nsKDEUtils
+    {
+    public:
+        /* Returns true if running inside a KDE session (regardless of whether there is KDE
+           support available for Firefox). This should be used e.g. when determining
+           dialog button order but not for code that requires the KDE support. */
+        static bool kdeSession();
+        /* Returns true if running inside a KDE session and KDE support is available
+           for Firefox. This should be used everywhere where the external helper is needed. */
+        static bool kdeSupport();
+        /* Executes the given helper command, returns true if helper returned success. */
+        static bool command( const nsTArray<nsCString>& command, nsTArray<nsCString>* output = NULL );
+        static bool command( nsIArray* command, nsIArray** output = NULL );
+        /* Like command(), but additionally blocks the parent widget like if there was
+           a modal dialog shown and enters the event loop (i.e. there are still paint updates,
+           this is for commands that take long). */
+        static bool commandBlockUi( const nsTArray<nsCString>& command, GtkWindow* parent, nsTArray<nsCString>* output = NULL );
+
+    private:
+        nsKDEUtils();
+        ~nsKDEUtils();
+        static nsKDEUtils* self();
+        bool startHelper();
+        void closeHelper();
+        void feedCommand( const nsTArray<nsCString>& command );
+        bool internalCommand( const nsTArray<nsCString>& command, GtkWindow* parent, bool isParent,
+            nsTArray<nsCString>* output );
+        FILE* commandFile;
+        FILE* replyFile;
+    };
+
+#endif // nsKDEUtils
diff --git a/uriloader/exthandler/moz.build b/uriloader/exthandler/moz.build
--- a/uriloader/exthandler/moz.build
+++ b/uriloader/exthandler/moz.build
@@ -77,17 +77,19 @@ else:
     SOURCES += [
         osdir + '/nsOSHelperAppService.cpp',
     ]
     if CONFIG['GNU_CXX']:
         CXXFLAGS += ['-Wno-error=shadow']
 
 if 'gtk' in CONFIG['MOZ_WIDGET_TOOLKIT']:
     UNIFIED_SOURCES += [
+        'unix/nsCommonRegistry.cpp',
         'unix/nsGNOMERegistry.cpp',
+	'unix/nsKDERegistry.cpp',
         'unix/nsMIMEInfoUnix.cpp',
     ]
 elif CONFIG['MOZ_WIDGET_TOOLKIT'] == 'android':
     UNIFIED_SOURCES += [
         'android/nsAndroidHandlerApp.cpp',
         'android/nsExternalSharingAppService.cpp',
         'android/nsExternalURLHandlerService.cpp',
         'android/nsMIMEInfoAndroid.cpp',
@@ -129,16 +131,17 @@ include('/ipc/chromium/chromium-config.m
 FINAL_LIBRARY = 'xul'
 
 LOCAL_INCLUDES += [
     '/docshell/base',
     '/dom/base',
     '/dom/ipc',
     '/netwerk/base',
     '/netwerk/protocol/http',
+    '/toolkit/xre',
 ]
 
 if CONFIG['MOZ_ENABLE_DBUS']:
     CXXFLAGS += CONFIG['TK_CFLAGS']
     CXXFLAGS += CONFIG['MOZ_DBUS_CFLAGS']
 
 if CONFIG['MOZ_WIDGET_TOOLKIT'] in ('gtk2', 'gtk3'):
     CXXFLAGS += CONFIG['TK_CFLAGS']
diff --git a/uriloader/exthandler/unix/nsCommonRegistry.cpp b/uriloader/exthandler/unix/nsCommonRegistry.cpp
new file mode 100644
--- /dev/null
+++ b/uriloader/exthandler/unix/nsCommonRegistry.cpp
@@ -0,0 +1,53 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsCommonRegistry.h"
+
+#include "nsGNOMERegistry.h"
+#include "nsKDERegistry.h"
+#include "nsString.h"
+#include "nsKDEUtils.h"
+
+/* static */ bool
+nsCommonRegistry::HandlerExists(const char *aProtocolScheme)
+{
+    if( nsKDEUtils::kdeSupport())
+        return nsKDERegistry::HandlerExists( aProtocolScheme );
+    return nsGNOMERegistry::HandlerExists( aProtocolScheme );
+}
+
+/* static */ nsresult
+nsCommonRegistry::LoadURL(nsIURI *aURL)
+{
+    if( nsKDEUtils::kdeSupport())
+        return nsKDERegistry::LoadURL( aURL );
+    return nsGNOMERegistry::LoadURL( aURL );
+}
+
+/* static */ void
+nsCommonRegistry::GetAppDescForScheme(const nsACString& aScheme,
+                                     nsAString& aDesc)
+{
+    if( nsKDEUtils::kdeSupport())
+        return nsKDERegistry::GetAppDescForScheme( aScheme, aDesc );
+    return nsGNOMERegistry::GetAppDescForScheme( aScheme, aDesc );
+}
+
+
+/* static */ already_AddRefed<nsMIMEInfoBase>
+nsCommonRegistry::GetFromExtension(const nsACString& aFileExt)
+{
+    if( nsKDEUtils::kdeSupport())
+        return nsKDERegistry::GetFromExtension( aFileExt );
+    return nsGNOMERegistry::GetFromExtension( aFileExt );
+}
+
+/* static */ already_AddRefed<nsMIMEInfoBase>
+nsCommonRegistry::GetFromType(const nsACString& aMIMEType)
+{
+    if( nsKDEUtils::kdeSupport())
+        return nsKDERegistry::GetFromType( aMIMEType );
+    return nsGNOMERegistry::GetFromType( aMIMEType );
+}
diff --git a/uriloader/exthandler/unix/nsCommonRegistry.h b/uriloader/exthandler/unix/nsCommonRegistry.h
new file mode 100644
--- /dev/null
+++ b/uriloader/exthandler/unix/nsCommonRegistry.h
@@ -0,0 +1,28 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef nsCommonRegistry_h__
+#define nsCommonRegistry_h__
+
+#include "nsIURI.h"
+#include "nsCOMPtr.h"
+
+class nsMIMEInfoBase;
+
+class nsCommonRegistry
+{
+ public:
+  static bool HandlerExists(const char *aProtocolScheme);
+
+  static nsresult LoadURL(nsIURI *aURL);
+
+  static void GetAppDescForScheme(const nsACString& aScheme,
+                                  nsAString& aDesc);
+
+  static already_AddRefed<nsMIMEInfoBase> GetFromExtension(const nsACString& aFileExt);
+
+  static already_AddRefed<nsMIMEInfoBase> GetFromType(const nsACString& aMIMEType);
+};
+
+#endif
diff --git a/uriloader/exthandler/unix/nsKDERegistry.cpp b/uriloader/exthandler/unix/nsKDERegistry.cpp
new file mode 100644
--- /dev/null
+++ b/uriloader/exthandler/unix/nsKDERegistry.cpp
@@ -0,0 +1,87 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsKDERegistry.h"
+#include "prlink.h"
+#include "prmem.h"
+#include "nsString.h"
+#include "nsMIMEInfoUnix.h"
+#include "nsAutoPtr.h"
+#include "nsKDEUtils.h"
+
+/* static */ bool
+nsKDERegistry::HandlerExists(const char *aProtocolScheme)
+{
+    nsTArray<nsCString> command;
+    command.AppendElement( NS_LITERAL_CSTRING( "HANDLEREXISTS" ));
+    command.AppendElement( nsAutoCString( aProtocolScheme ));
+    return nsKDEUtils::command( command );
+}
+
+/* static */ nsresult
+nsKDERegistry::LoadURL(nsIURI *aURL)
+{
+    nsTArray<nsCString> command;
+    command.AppendElement( NS_LITERAL_CSTRING( "OPEN" ));
+    nsCString url;
+    aURL->GetSpec( url );
+    command.AppendElement( url );
+    bool rv = nsKDEUtils::command( command );
+    if (!rv)
+      return NS_ERROR_FAILURE;
+
+    return NS_OK;
+}
+
+/* static */ void
+nsKDERegistry::GetAppDescForScheme(const nsACString& aScheme,
+                                     nsAString& aDesc)
+{
+    nsTArray<nsCString> command;
+    command.AppendElement( NS_LITERAL_CSTRING( "GETAPPDESCFORSCHEME" ));
+    command.AppendElement( aScheme );
+    nsTArray<nsCString> output;
+    if( nsKDEUtils::command( command, &output ) && output.Length() == 1 )
+        CopyUTF8toUTF16( output[ 0 ], aDesc );
+}
+
+
+/* static */ already_AddRefed<nsMIMEInfoBase>
+nsKDERegistry::GetFromExtension(const nsACString& aFileExt)
+{
+    NS_ASSERTION(aFileExt[0] != '.', "aFileExt shouldn't start with a dot");
+    nsTArray<nsCString> command;
+    command.AppendElement( NS_LITERAL_CSTRING( "GETFROMEXTENSION" ));
+    command.AppendElement( aFileExt );
+    return GetFromHelper( command );
+}
+
+/* static */ already_AddRefed<nsMIMEInfoBase>
+nsKDERegistry::GetFromType(const nsACString& aMIMEType)
+{
+    nsTArray<nsCString> command;
+    command.AppendElement( NS_LITERAL_CSTRING( "GETFROMTYPE" ));
+    command.AppendElement( aMIMEType );
+    return GetFromHelper( command );
+}
+
+/* static */ already_AddRefed<nsMIMEInfoBase>
+nsKDERegistry::GetFromHelper(const nsTArray<nsCString>& command)
+{
+    nsTArray<nsCString> output;
+    if( nsKDEUtils::command( command, &output ) && output.Length() == 3 )
+        {
+        nsCString mimetype = output[ 0 ];
+        RefPtr<nsMIMEInfoUnix> mimeInfo = new nsMIMEInfoUnix( mimetype );
+        NS_ENSURE_TRUE(mimeInfo, nullptr);
+        nsCString description = output[ 1 ];
+        mimeInfo->SetDescription(NS_ConvertUTF8toUTF16(description));
+        nsCString handlerAppName = output[ 2 ];
+        mimeInfo->SetDefaultDescription(NS_ConvertUTF8toUTF16(handlerAppName));
+        mimeInfo->SetPreferredAction(nsIMIMEInfo::useSystemDefault);
+        return mimeInfo.forget();
+        }
+    return nullptr;
+}
diff --git a/uriloader/exthandler/unix/nsKDERegistry.h b/uriloader/exthandler/unix/nsKDERegistry.h
new file mode 100644
--- /dev/null
+++ b/uriloader/exthandler/unix/nsKDERegistry.h
@@ -0,0 +1,34 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef nsKDERegistry_h__
+#define nsKDERegistry_h__
+
+#include "nsIURI.h"
+#include "nsCOMPtr.h"
+#include "nsTArray.h"
+
+class nsMIMEInfoBase;
+//class nsAutoCString;
+//class nsCString;
+
+class nsKDERegistry
+{
+ public:
+  static bool HandlerExists(const char *aProtocolScheme);
+
+  static nsresult LoadURL(nsIURI *aURL);
+
+  static void GetAppDescForScheme(const nsACString& aScheme,
+                                  nsAString& aDesc);
+
+  static already_AddRefed<nsMIMEInfoBase> GetFromExtension(const nsACString& aFileExt);
+
+  static already_AddRefed<nsMIMEInfoBase> GetFromType(const nsACString& aMIMEType);
+ private:
+  static already_AddRefed<nsMIMEInfoBase> GetFromHelper(const nsTArray<nsCString>& command);
+
+};
+
+#endif //nsKDERegistry_h__
diff --git a/uriloader/exthandler/unix/nsMIMEInfoUnix.cpp b/uriloader/exthandler/unix/nsMIMEInfoUnix.cpp
--- a/uriloader/exthandler/unix/nsMIMEInfoUnix.cpp
+++ b/uriloader/exthandler/unix/nsMIMEInfoUnix.cpp
@@ -1,50 +1,53 @@
 /* -*- Mode: C++; tab-width: 3; indent-tabs-mode: nil; c-basic-offset: 2 -*-
  *
  * This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 #include "nsMIMEInfoUnix.h"
-#include "nsGNOMERegistry.h"
+#include "nsCommonRegistry.h"
 #include "nsIGIOService.h"
 #include "nsNetCID.h"
 #include "nsIIOService.h"
 #include "nsAutoPtr.h"
 #ifdef MOZ_ENABLE_DBUS
 #include "nsDBusHandlerApp.h"
 #endif
+#if defined(XP_UNIX) && !defined(XP_MACOSX)
+#include "nsKDEUtils.h"
+#endif
 
 nsresult
 nsMIMEInfoUnix::LoadUriInternal(nsIURI * aURI)
 {
-  return nsGNOMERegistry::LoadURL(aURI);
+  return nsCommonRegistry::LoadURL(aURI);
 }
 
 NS_IMETHODIMP
 nsMIMEInfoUnix::GetHasDefaultHandler(bool *_retval)
 {
   // if mDefaultApplication is set, it means the application has been set from
   // either /etc/mailcap or ${HOME}/.mailcap, in which case we don't want to
   // give the GNOME answer.
   if (mDefaultApplication)
     return nsMIMEInfoImpl::GetHasDefaultHandler(_retval);
 
   *_retval = false;
 
   if (mClass == eProtocolInfo) {
-    *_retval = nsGNOMERegistry::HandlerExists(mSchemeOrType.get());
+    *_retval = nsCommonRegistry::HandlerExists(mSchemeOrType.get());
   } else {
-    RefPtr<nsMIMEInfoBase> mimeInfo = nsGNOMERegistry::GetFromType(mSchemeOrType);
+    RefPtr<nsMIMEInfoBase> mimeInfo = nsCommonRegistry::GetFromType(mSchemeOrType);
     if (!mimeInfo) {
       nsAutoCString ext;
       nsresult rv = GetPrimaryExtension(ext);
       if (NS_SUCCEEDED(rv)) {
-        mimeInfo = nsGNOMERegistry::GetFromExtension(ext);
+        mimeInfo = nsCommonRegistry::GetFromExtension(ext);
       }
     }
     if (mimeInfo)
       *_retval = true;
   }
 
   if (*_retval)
     return NS_OK;
@@ -79,16 +82,33 @@ nsMIMEInfoUnix::LaunchDefaultWithFile(ns
     ContentAction::Action::defaultActionForFile(uri, QString(mSchemeOrType.get()));
   if (action.isValid()) {
     action.trigger();
     return NS_OK;
   }
   return NS_ERROR_FAILURE;
 #endif
 
+  if( nsKDEUtils::kdeSupport()) {
+    bool supports;
+    if( NS_SUCCEEDED( GetHasDefaultHandler( &supports )) && supports ) {
+      nsTArray<nsCString> command;
+      command.AppendElement( NS_LITERAL_CSTRING( "OPEN" ));
+      command.AppendElement( nativePath );
+      command.AppendElement( NS_LITERAL_CSTRING( "MIMETYPE" ));
+      command.AppendElement( mSchemeOrType );
+      if( nsKDEUtils::command( command ))
+        return NS_OK;
+    }
+    if (!mDefaultApplication)
+      return NS_ERROR_FILE_NOT_FOUND;
+
+    return LaunchWithIProcess(mDefaultApplication, nativePath);
+  }
+
   nsCOMPtr<nsIGIOService> giovfs = do_GetService(NS_GIOSERVICE_CONTRACTID);
   if (!giovfs) {
     return NS_ERROR_FAILURE;
   }
 
   // nsGIOMimeApp->Launch wants a URI string instead of local file
   nsresult rv;
   nsCOMPtr<nsIIOService> ioservice = do_GetService(NS_IOSERVICE_CONTRACTID, &rv);
diff --git a/uriloader/exthandler/unix/nsOSHelperAppService.cpp b/uriloader/exthandler/unix/nsOSHelperAppService.cpp
--- a/uriloader/exthandler/unix/nsOSHelperAppService.cpp
+++ b/uriloader/exthandler/unix/nsOSHelperAppService.cpp
@@ -5,17 +5,17 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 #include <sys/types.h>
 #include <sys/stat.h>
 
 #include "nsOSHelperAppService.h"
 #include "nsMIMEInfoUnix.h"
 #ifdef MOZ_WIDGET_GTK
-#include "nsGNOMERegistry.h"
+#include "nsCommonRegistry.h"
 #endif
 #include "nsISupports.h"
 #include "nsString.h"
 #include "nsReadableUtils.h"
 #include "nsUnicharUtils.h"
 #include "nsIURL.h"
 #include "nsIFileStreams.h"
 #include "nsILineInputStream.h"
@@ -1128,17 +1128,17 @@ nsOSHelperAppService::GetHandlerAndDescr
 
 nsresult nsOSHelperAppService::OSProtocolHandlerExists(const char * aProtocolScheme, bool * aHandlerExists)
 {
   nsresult rv = NS_OK;
 
   if (!XRE_IsContentProcess()) {
 #ifdef MOZ_WIDGET_GTK
     // Check the GNOME registry for a protocol handler
-    *aHandlerExists = nsGNOMERegistry::HandlerExists(aProtocolScheme);
+    *aHandlerExists = nsCommonRegistry::HandlerExists(aProtocolScheme);
 #else
     *aHandlerExists = false;
 #endif
   } else {
     *aHandlerExists = false;
     nsCOMPtr<nsIHandlerService> handlerSvc = do_GetService(NS_HANDLERSERVICE_CONTRACTID, &rv);
     if (NS_SUCCEEDED(rv) && handlerSvc) {
       rv = handlerSvc->ExistsForProtocol(nsCString(aProtocolScheme), aHandlerExists);
@@ -1146,17 +1146,17 @@ nsresult nsOSHelperAppService::OSProtoco
   }
 
   return rv;
 }
 
 NS_IMETHODIMP nsOSHelperAppService::GetApplicationDescription(const nsACString& aScheme, nsAString& _retval)
 {
 #ifdef MOZ_WIDGET_GTK
-  nsGNOMERegistry::GetAppDescForScheme(aScheme, _retval);
+  nsCommonRegistry::GetAppDescForScheme(aScheme, _retval);
   return _retval.IsEmpty() ? NS_ERROR_NOT_AVAILABLE : NS_OK;
 #else
   return NS_ERROR_NOT_AVAILABLE;
 #endif
 }
 
 nsresult nsOSHelperAppService::GetFileTokenForPath(const char16_t * platformAppPath, nsIFile ** aFile)
 {
@@ -1243,17 +1243,17 @@ nsOSHelperAppService::GetFromExtension(c
                                          mime_types_description,
                                          true);
 
   if (NS_FAILED(rv) || majorType.IsEmpty()) {
 
 #ifdef MOZ_WIDGET_GTK
     LOG(("Looking in GNOME registry\n"));
     RefPtr<nsMIMEInfoBase> gnomeInfo =
-      nsGNOMERegistry::GetFromExtension(aFileExt);
+      nsCommonRegistry::GetFromExtension(aFileExt);
     if (gnomeInfo) {
       LOG(("Got MIMEInfo from GNOME registry\n"));
       return gnomeInfo.forget();
     }
 #endif
 
     rv = LookUpTypeAndDescription(NS_ConvertUTF8toUTF16(aFileExt),
                                   majorType,
@@ -1364,17 +1364,17 @@ nsOSHelperAppService::GetFromType(const 
   nsAutoString extensions, mime_types_description;
   LookUpExtensionsAndDescription(majorType,
                                  minorType,
                                  extensions,
                                  mime_types_description);
 
 #ifdef MOZ_WIDGET_GTK
   if (handler.IsEmpty()) {
-    RefPtr<nsMIMEInfoBase> gnomeInfo = nsGNOMERegistry::GetFromType(aMIMEType);
+    RefPtr<nsMIMEInfoBase> gnomeInfo = nsCommonRegistry::GetFromType(aMIMEType);
     if (gnomeInfo) {
       LOG(("Got MIMEInfo from GNOME registry without extensions; setting them "
            "to %s\n", NS_LossyConvertUTF16toASCII(extensions).get()));
 
       NS_ASSERTION(!gnomeInfo->HasExtensions(), "How'd that happen?");
       gnomeInfo->SetFileExtensions(NS_ConvertUTF16toUTF8(extensions));
       return gnomeInfo.forget();
     }
diff --git a/widget/gtk/moz.build b/widget/gtk/moz.build
--- a/widget/gtk/moz.build
+++ b/widget/gtk/moz.build
@@ -109,16 +109,17 @@ else:
 include('/ipc/chromium/chromium-config.mozbuild')
 
 FINAL_LIBRARY = 'xul'
 
 LOCAL_INCLUDES += [
     '/layout/generic',
     '/layout/xul',
     '/other-licenses/atk-1.0',
+    '/toolkit/xre',
     '/widget',
     '/widget/headless',
 ]
 
 if CONFIG['MOZ_X11']:
     LOCAL_INCLUDES += [
         '/widget/x11',
     ]
diff --git a/widget/gtk/nsFilePicker.cpp b/widget/gtk/nsFilePicker.cpp
--- a/widget/gtk/nsFilePicker.cpp
+++ b/widget/gtk/nsFilePicker.cpp
@@ -4,32 +4,34 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 #include "mozilla/Types.h"
 #include <sys/types.h>
 #include <sys/stat.h>
 #include <unistd.h>
 
 #include <gtk/gtk.h>
+#include <gdk/gdkx.h>
 
 #include "nsGtkUtils.h"
 #include "nsIFileURL.h"
 #include "nsIURI.h"
 #include "nsIWidget.h"
 #include "nsIFile.h"
 #include "nsIStringBundle.h"
 
 #include "nsArrayEnumerator.h"
 #include "nsMemory.h"
 #include "nsEnumeratorUtils.h"
 #include "nsNetUtil.h"
 #include "nsReadableUtils.h"
 #include "mozcontainer.h"
 
 #include "nsFilePicker.h"
+#include "nsKDEUtils.h"
 
 using namespace mozilla;
 
 #define MAX_PREVIEW_SIZE 180
 // bug 1184009
 #define MAX_PREVIEW_SOURCE_SIZE 4096
 
 nsIFile *nsFilePicker::mPrevDisplayDirectory = nullptr;
@@ -246,17 +248,19 @@ nsFilePicker::AppendFilters(int32_t aFil
   return nsBaseFilePicker::AppendFilters(aFilterMask);
 }
 
 NS_IMETHODIMP
 nsFilePicker::AppendFilter(const nsAString& aTitle, const nsAString& aFilter)
 {
   if (aFilter.EqualsLiteral("..apps")) {
     // No platform specific thing we can do here, really....
-    return NS_OK;
+    // Unless it's KDE.
+    if( mMode != modeOpen || !nsKDEUtils::kdeSupport())
+      return NS_OK;
   }
 
   nsAutoCString filter, name;
   CopyUTF16toUTF8(aFilter, filter);
   CopyUTF16toUTF8(aTitle, name);
 
   mFilters.AppendElement(filter);
   mFilterNames.AppendElement(name);
@@ -371,16 +375,39 @@ nsFilePicker::Show(int16_t *aReturn)
 
 NS_IMETHODIMP
 nsFilePicker::Open(nsIFilePickerShownCallback *aCallback)
 {
   // Can't show two dialogs concurrently with the same filepicker
   if (mRunning)
     return NS_ERROR_NOT_AVAILABLE;
 
+  // KDE file picker is not handled via callback
+  if( nsKDEUtils::kdeSupport()) {
+    mCallback = aCallback;
+    mRunning = true;
+    NS_ADDREF_THIS();
+    g_idle_add([](gpointer data) -> gboolean {
+      nsFilePicker* queuedPicker = (nsFilePicker*) data;
+      int16_t result;
+      queuedPicker->kdeFileDialog(&result);
+      if (queuedPicker->mCallback) {
+        queuedPicker->mCallback->Done(result);
+        queuedPicker->mCallback = nullptr;
+      } else {
+        queuedPicker->mResult = result;
+      }
+      queuedPicker->mRunning = false;
+      NS_RELEASE(queuedPicker);
+      return G_SOURCE_REMOVE;
+    }, this);
+
+    return NS_OK;
+  }
+
   nsCString title;
   title.Adopt(ToNewUTF8String(mTitle));
 
   GtkWindow *parent_widget =
     GTK_WINDOW(mParentWidget->GetNativeData(NS_NATIVE_SHELLWIDGET));
 
   GtkFileChooserAction action = GetGtkFileChooserAction(mMode);
 
@@ -603,8 +630,233 @@ nsFilePicker::Done(GtkWidget* file_choos
   if (mCallback) {
     mCallback->Done(result);
     mCallback = nullptr;
   } else {
     mResult = result;
   }
   NS_RELEASE_THIS();
 }
+
+nsCString nsFilePicker::kdeMakeFilter( int index )
+    {
+    nsCString buf = mFilters[ index ];
+    for( PRUint32 i = 0;
+         i < buf.Length();
+         ++i )
+        if( buf[ i ] == ';' ) // KDE separates just using spaces
+            buf.SetCharAt( ' ', i );
+    if (!mFilterNames[index].IsEmpty())
+        {
+        buf += "|";
+        buf += mFilterNames[index].get();
+        }
+    return buf;
+    }
+
+static PRInt32 windowToXid( nsIWidget* widget )
+    {
+    GtkWindow *parent_widget = GTK_WINDOW(widget->GetNativeData(NS_NATIVE_SHELLWIDGET));
+    GdkWindow* gdk_window = gtk_widget_get_window( gtk_widget_get_toplevel( GTK_WIDGET( parent_widget )));
+    return GDK_WINDOW_XID( gdk_window );
+    }
+
+NS_IMETHODIMP nsFilePicker::kdeFileDialog(PRInt16 *aReturn)
+    {
+    NS_ENSURE_ARG_POINTER(aReturn);
+
+    if( mMode == modeOpen && mFilters.Length() == 1 && mFilters[ 0 ].EqualsLiteral( "..apps" ))
+        return kdeAppsDialog( aReturn );
+
+    nsCString title;
+    title.Adopt(ToNewUTF8String(mTitle));
+
+    const char* arg = NULL;
+    if( mAllowURLs )
+        {
+        switch( mMode )
+            {
+            case nsIFilePicker::modeOpen:
+            case nsIFilePicker::modeOpenMultiple:
+                arg = "GETOPENURL";
+                break;
+            case nsIFilePicker::modeSave:
+                arg = "GETSAVEURL";
+                break;
+            case nsIFilePicker::modeGetFolder:
+                arg = "GETDIRECTORYURL";
+                break;
+            }
+        }
+    else
+        {
+        switch( mMode )
+            {
+            case nsIFilePicker::modeOpen:
+            case nsIFilePicker::modeOpenMultiple:
+                arg = "GETOPENFILENAME";
+                break;
+            case nsIFilePicker::modeSave:
+                arg = "GETSAVEFILENAME";
+                break;
+            case nsIFilePicker::modeGetFolder:
+                arg = "GETDIRECTORYFILENAME";
+                break;
+            }
+        }
+
+  nsAutoCString directory;
+  if (mDisplayDirectory) {
+    mDisplayDirectory->GetNativePath(directory);
+  } else if (mPrevDisplayDirectory) {
+    mPrevDisplayDirectory->GetNativePath(directory);
+  }
+
+    nsAutoCString startdir;
+  if (!directory.IsEmpty()) {
+    startdir = directory;
+  }
+  if (mMode == nsIFilePicker::modeSave) {
+    if( !startdir.IsEmpty())
+      {
+      startdir += "/";
+      startdir += ToNewUTF8String(mDefault);
+      }
+    else
+      startdir = ToNewUTF8String(mDefault);
+  }
+
+    nsAutoCString filters;
+    PRInt32 count = mFilters.Length();
+    if( count == 0 ) //just in case
+        filters = "*";
+    else
+        {
+        filters = kdeMakeFilter( 0 );
+        for (PRInt32 i = 1; i < count; ++i)
+            {
+            filters += "\n";
+            filters += kdeMakeFilter( i );
+            }
+        }
+
+    nsTArray<nsCString> command;
+    command.AppendElement( nsAutoCString( arg ));
+    command.AppendElement( startdir );
+    if( mMode != nsIFilePicker::modeGetFolder )
+        {
+        command.AppendElement( filters );
+        nsAutoCString selected;
+        selected.AppendInt( mSelectedType );
+        command.AppendElement( selected );
+        }
+    command.AppendElement( title );
+    if( mMode == nsIFilePicker::modeOpenMultiple )
+        command.AppendElement( NS_LITERAL_CSTRING( "MULTIPLE" ));
+    if( PRInt32 xid = windowToXid( mParentWidget ))
+        {
+        command.AppendElement( NS_LITERAL_CSTRING( "PARENT" ));
+        nsAutoCString parent;
+        parent.AppendInt( xid );
+        command.AppendElement( parent );
+        }
+
+    nsTArray<nsCString> output;
+    if( nsKDEUtils::commandBlockUi( command, GTK_WINDOW(mParentWidget->GetNativeData(NS_NATIVE_SHELLWIDGET)), &output ))
+        {
+        *aReturn = nsIFilePicker::returnOK;
+        mFiles.Clear();
+        if( mMode != nsIFilePicker::modeGetFolder )
+            {
+            mSelectedType = atoi( output[ 0 ].get());
+            output.RemoveElementAt( 0 );
+            }
+        if (mMode == nsIFilePicker::modeOpenMultiple)
+            {
+            mFileURL.Truncate();
+            PRUint32 count = output.Length();
+            for( PRUint32 i = 0;
+                 i < count;
+                 ++i )
+                {
+                nsCOMPtr<nsIFile> localfile;
+                nsresult rv = NS_NewNativeLocalFile( output[ i ],
+                                      PR_FALSE,
+                                      getter_AddRefs(localfile));
+                if (NS_SUCCEEDED(rv))
+                    mFiles.AppendObject(localfile);
+                }
+            }
+        else
+            {
+            if( output.Length() == 0 )
+                mFileURL = nsCString();
+            else if( mAllowURLs )
+                mFileURL = output[ 0 ];
+            else // GetFile() actually requires it to be url even for local files :-/
+                {
+                mFileURL = nsCString( "file://" );
+                mFileURL.Append( output[ 0 ] );
+                }
+            }
+  // Remember last used directory.
+  nsCOMPtr<nsIFile> file;
+  GetFile(getter_AddRefs(file));
+  if (file) {
+    nsCOMPtr<nsIFile> dir;
+    file->GetParent(getter_AddRefs(dir));
+    nsCOMPtr<nsIFile> localDir(do_QueryInterface(dir));
+    if (localDir) {
+      localDir.swap(mPrevDisplayDirectory);
+    }
+  }
+        if (mMode == nsIFilePicker::modeSave)
+            {
+            nsCOMPtr<nsIFile> file;
+            GetFile(getter_AddRefs(file));
+            if (file)
+                {
+                bool exists = false;
+                file->Exists(&exists);
+                if (exists) // TODO do overwrite check in the helper app
+                    *aReturn = nsIFilePicker::returnReplace;
+                }
+            }
+        }
+    else
+        {
+        *aReturn = nsIFilePicker::returnCancel;
+        }
+    return NS_OK;
+    }
+
+
+NS_IMETHODIMP nsFilePicker::kdeAppsDialog(PRInt16 *aReturn)
+    {
+    NS_ENSURE_ARG_POINTER(aReturn);
+
+    nsCString title;
+    title.Adopt(ToNewUTF8String(mTitle));
+
+    nsTArray<nsCString> command;
+    command.AppendElement( NS_LITERAL_CSTRING( "APPSDIALOG" ));
+    command.AppendElement( title );
+    if( PRInt32 xid = windowToXid( mParentWidget ))
+        {
+        command.AppendElement( NS_LITERAL_CSTRING( "PARENT" ));
+        nsAutoCString parent;
+        parent.AppendInt( xid );
+        command.AppendElement( parent );
+        }
+
+    nsTArray<nsCString> output;
+    if( nsKDEUtils::commandBlockUi( command, GTK_WINDOW(mParentWidget->GetNativeData(NS_NATIVE_SHELLWIDGET)), &output ))
+        {
+        *aReturn = nsIFilePicker::returnOK;
+        mFileURL = output.Length() > 0 ? output[ 0 ] : nsCString();
+        }
+    else
+        {
+        *aReturn = nsIFilePicker::returnCancel;
+        }
+    return NS_OK;
+    }
+
diff --git a/widget/gtk/nsFilePicker.h b/widget/gtk/nsFilePicker.h
--- a/widget/gtk/nsFilePicker.h
+++ b/widget/gtk/nsFilePicker.h
@@ -69,14 +69,20 @@ protected:
   nsString  mDefaultExtension;
 
   nsTArray<nsCString> mFilters;
   nsTArray<nsCString> mFilterNames;
 
 private:
   static nsIFile *mPrevDisplayDirectory;
 
+  bool kdeRunning();
+  bool getKdeRunning();
+  NS_IMETHODIMP kdeFileDialog(PRInt16 *aReturn);
+  NS_IMETHODIMP kdeAppsDialog(PRInt16 *aReturn);
+  nsCString kdeMakeFilter( int index );
+
 #if (MOZ_WIDGET_GTK == 3)
   GtkFileChooserWidget *mFileChooserDelegate;
 #endif
 };
 
 #endif
diff --git a/xpcom/components/ManifestParser.cpp b/xpcom/components/ManifestParser.cpp
--- a/xpcom/components/ManifestParser.cpp
+++ b/xpcom/components/ManifestParser.cpp
@@ -33,16 +33,17 @@
 #include "nsTextFormatter.h"
 #include "nsVersionComparator.h"
 #include "nsXPCOMCIDInternal.h"
 
 #include "nsIConsoleService.h"
 #include "nsIScriptError.h"
 #include "nsIXULAppInfo.h"
 #include "nsIXULRuntime.h"
+#include "nsKDEUtils.h"
 
 using namespace mozilla;
 
 struct ManifestDirective
 {
   const char* directive;
   int argc;
 
@@ -466,16 +467,17 @@ ParseManifest(NSLocationType aType, File
   NS_NAMED_LITERAL_STRING(kRemoteEnabled, "remoteenabled");
   NS_NAMED_LITERAL_STRING(kRemoteRequired, "remoterequired");
   NS_NAMED_LITERAL_STRING(kApplication, "application");
   NS_NAMED_LITERAL_STRING(kAppVersion, "appversion");
   NS_NAMED_LITERAL_STRING(kGeckoVersion, "platformversion");
   NS_NAMED_LITERAL_STRING(kOs, "os");
   NS_NAMED_LITERAL_STRING(kOsVersion, "osversion");
   NS_NAMED_LITERAL_STRING(kABI, "abi");
+  NS_NAMED_LITERAL_STRING(kDesktop, "desktop");
   NS_NAMED_LITERAL_STRING(kProcess, "process");
 #if defined(MOZ_WIDGET_ANDROID)
   NS_NAMED_LITERAL_STRING(kTablet, "tablet");
 #endif
 
   NS_NAMED_LITERAL_STRING(kMain, "main");
   NS_NAMED_LITERAL_STRING(kContent, "content");
 
@@ -526,44 +528,49 @@ ParseManifest(NSLocationType aType, File
         CopyUTF8toUTF16(s, abi);
         abi.Insert(char16_t('_'), 0);
         abi.Insert(osTarget, 0);
       }
     }
   }
 
   nsAutoString osVersion;
+  nsAutoString desktop;
 #if defined(XP_WIN)
 #pragma warning(push)
 #pragma warning(disable:4996) // VC12+ deprecates GetVersionEx
   OSVERSIONINFO info = { sizeof(OSVERSIONINFO) };
   if (GetVersionEx(&info)) {
     nsTextFormatter::ssprintf(osVersion, u"%ld.%ld",
                               info.dwMajorVersion,
                               info.dwMinorVersion);
   }
+  desktop = NS_LITERAL_STRING("win");
 #pragma warning(pop)
 #elif defined(MOZ_WIDGET_COCOA)
   SInt32 majorVersion = nsCocoaFeatures::OSXVersionMajor();
   SInt32 minorVersion = nsCocoaFeatures::OSXVersionMinor();
   nsTextFormatter::ssprintf(osVersion, u"%ld.%ld",
                             majorVersion,
                             minorVersion);
+  desktop = NS_LITERAL_STRING("macosx");
 #elif defined(MOZ_WIDGET_GTK)
   nsTextFormatter::ssprintf(osVersion, u"%ld.%ld",
                             gtk_major_version,
                             gtk_minor_version);
+  desktop = nsKDEUtils::kdeSession() ? NS_LITERAL_STRING("kde") : NS_LITERAL_STRING("gnome");
 #elif defined(MOZ_WIDGET_ANDROID)
   bool isTablet = false;
   if (mozilla::AndroidBridge::Bridge()) {
     mozilla::AndroidBridge::Bridge()->GetStaticStringField("android/os/Build$VERSION",
                                                            "RELEASE",
                                                            osVersion);
     isTablet = java::GeckoAppShell::IsTablet();
   }
+  desktop = NS_LITERAL_STRING("android");
 #endif
 
   if (XRE_IsContentProcess()) {
     process = kContent;
   } else {
     process = kMain;
   }
 
@@ -666,25 +673,27 @@ ParseManifest(NSLocationType aType, File
     TriState stOsVersion = eUnspecified;
     TriState stOs = eUnspecified;
     TriState stABI = eUnspecified;
     TriState stProcess = eUnspecified;
 #if defined(MOZ_WIDGET_ANDROID)
     TriState stTablet = eUnspecified;
 #endif
     int flags = 0;
+    TriState stDesktop = eUnspecified;
 
     while ((token = nsCRT::strtok(whitespace, kWhitespace, &whitespace)) &&
            ok) {
       ToLowerCase(token);
       NS_ConvertASCIItoUTF16 wtoken(token);
 
       if (CheckStringFlag(kApplication, wtoken, appID, stApp) ||
           CheckOsFlag(kOs, wtoken, osTarget, stOs) ||
           CheckStringFlag(kABI, wtoken, abi, stABI) ||
+          CheckStringFlag(kDesktop, wtoken, desktop, stDesktop) ||
           CheckStringFlag(kProcess, wtoken, process, stProcess) ||
           CheckVersionFlag(kOsVersion, wtoken, osVersion, stOsVersion) ||
           CheckVersionFlag(kAppVersion, wtoken, appVersion, stAppVersion) ||
           CheckVersionFlag(kGeckoVersion, wtoken, geckoVersion, stGeckoVersion)) {
         continue;
       }
 
 #if defined(MOZ_WIDGET_ANDROID)
@@ -729,16 +738,17 @@ ParseManifest(NSLocationType aType, File
     }
 
     if (!ok ||
         stApp == eBad ||
         stAppVersion == eBad ||
         stGeckoVersion == eBad ||
         stOs == eBad ||
         stOsVersion == eBad ||
+        stDesktop == eBad ||
 #ifdef MOZ_WIDGET_ANDROID
         stTablet == eBad ||
 #endif
         stABI == eBad ||
         stProcess == eBad) {
       continue;
     }
 
diff --git a/xpcom/components/moz.build b/xpcom/components/moz.build
--- a/xpcom/components/moz.build
+++ b/xpcom/components/moz.build
@@ -44,12 +44,13 @@ FINAL_LIBRARY = 'xul'
 LOCAL_INCLUDES += [
     '!..',
     '../base',
     '../build',
     '../ds',
     '../reflect/xptinfo',
     '/chrome',
     '/modules/libjar',
+    '/toolkit/xre'
 ]
 
 if 'gtk' in CONFIG['MOZ_WIDGET_TOOLKIT']:
     CXXFLAGS += CONFIG['TK_CFLAGS']
diff --git a/xpcom/io/nsLocalFileUnix.cpp b/xpcom/io/nsLocalFileUnix.cpp
--- a/xpcom/io/nsLocalFileUnix.cpp
+++ b/xpcom/io/nsLocalFileUnix.cpp
@@ -45,16 +45,17 @@
 #include "prproces.h"
 #include "nsIDirectoryEnumerator.h"
 #include "nsISimpleEnumerator.h"
 #include "private/pprio.h"
 #include "prlink.h"
 
 #ifdef MOZ_WIDGET_GTK
 #include "nsIGIOService.h"
+#include "nsKDEUtils.h"
 #endif
 
 #ifdef MOZ_WIDGET_COCOA
 #include <Carbon/Carbon.h>
 #include "CocoaFileUtils.h"
 #include "prmem.h"
 #include "plbase64.h"
 
@@ -1938,59 +1939,74 @@ nsLocalFile::SetPersistentDescriptor(con
   return InitWithNativePath(aPersistentDescriptor);
 #endif
 }
 
 NS_IMETHODIMP
 nsLocalFile::Reveal()
 {
 #ifdef MOZ_WIDGET_GTK
-  nsCOMPtr<nsIGIOService> giovfs = do_GetService(NS_GIOSERVICE_CONTRACTID);
-  if (!giovfs) {
-    return NS_ERROR_FAILURE;
-  }
+  nsAutoCString url;
 
   bool isDirectory;
   if (NS_FAILED(IsDirectory(&isDirectory))) {
     return NS_ERROR_FAILURE;
   }
 
+  nsCOMPtr<nsIGIOService> giovfs = do_GetService(NS_GIOSERVICE_CONTRACTID);
   if (isDirectory) {
-    return giovfs->ShowURIForInput(mPath);
+    url = mPath;
   }
   if (NS_SUCCEEDED(giovfs->OrgFreedesktopFileManager1ShowItems(mPath))) {
     return NS_OK;
   }
   nsCOMPtr<nsIFile> parentDir;
   nsAutoCString dirPath;
   if (NS_FAILED(GetParent(getter_AddRefs(parentDir)))) {
     return NS_ERROR_FAILURE;
   }
   if (NS_FAILED(parentDir->GetNativePath(dirPath))) {
     return NS_ERROR_FAILURE;
   }
 
-  return giovfs->ShowURIForInput(dirPath);
+  url = dirPath;
 #elif defined(MOZ_WIDGET_COCOA)
   CFURLRef url;
   if (NS_SUCCEEDED(GetCFURL(&url))) {
     nsresult rv = CocoaFileUtils::RevealFileInFinder(url);
     ::CFRelease(url);
     return rv;
   }
   return NS_ERROR_FAILURE;
 #else
   return NS_ERROR_FAILURE;
 #endif
+  if(nsKDEUtils::kdeSupport()) {
+    nsTArray<nsCString> command;
+    command.AppendElement( NS_LITERAL_CSTRING("REVEAL") );
+    command.AppendElement( mPath );
+    return nsKDEUtils::command( command ) ? NS_OK : NS_ERROR_FAILURE;
+  }
+
+  if (!giovfs)
+    return NS_ERROR_FAILURE;
+
+  return giovfs->ShowURIForInput(url);
 }
 
 NS_IMETHODIMP
 nsLocalFile::Launch()
 {
 #ifdef MOZ_WIDGET_GTK
+  if( nsKDEUtils::kdeSupport()) {
+    nsTArray<nsCString> command;
+    command.AppendElement( NS_LITERAL_CSTRING("OPEN") );
+    command.AppendElement( mPath );
+    return nsKDEUtils::command( command ) ? NS_OK : NS_ERROR_FAILURE;
+  }
   nsCOMPtr<nsIGIOService> giovfs = do_GetService(NS_GIOSERVICE_CONTRACTID);
   if (!giovfs) {
     return NS_ERROR_FAILURE;
   }
 
   return giovfs->ShowURIForInput(mPath);
 #elif defined(MOZ_ENABLE_CONTENTACTION)
   QUrl uri = QUrl::fromLocalFile(QString::fromUtf8(mPath.get()));