diff -ur lyx-2.1.0.orig/lib/configure.py lyx-2.1.0/lib/configure.py
--- lyx-2.1.0.orig/lib/configure.py	2014-04-13 19:23:17.000000000 +0200
+++ lyx-2.1.0/lib/configure.py	2014-04-14 22:48:03.871041731 +0200
@@ -594,7 +594,7 @@
 \Format tiff       tif     TIFF                   "" "%s"	"%s"	""	"image/tiff"
 \Format xbm        xbm     XBM                    "" "%s"	"%s"	""	"image/x-xbitmap"
 \Format xpm        xpm     XPM                    "" "%s"	"%s"	""	"image/x-xpixmap"'''
-    path, iv = checkViewerNoRC('a raster image viewer', ['xv', 'kview', 'gimp-remote', 'gimp'], rc_entry = [imageformats])
+    path, iv = checkViewerNoRC('a raster image viewer', ['xdg-open', 'xv', 'kview', 'gimp-remote', 'gimp'], rc_entry = [imageformats])
     path, ie = checkEditorNoRC('a raster image editor', ['gimp-remote', 'gimp'], rc_entry = [imageformats])
     addToRC(imageformats % \
         (iv, ie, iv, ie, iv, ie, iv, ie, iv, ie, iv, ie, iv, ie, iv, ie, iv, ie, iv, ie) )
@@ -633,7 +633,7 @@
 \Format excel      xls    "Excel spreadsheet"      "" "" "%%"    "document"	"application/vnd.ms-excel"
 \Format oocalc     ods    "OpenOffice spreadsheet" "" "" "%%"    "document"	"application/vnd.oasis.opendocument.spreadsheet"'''])
  #
-    checkViewer('an HTML previewer', ['firefox', 'mozilla file://$$p$$i', 'netscape'],
+    checkViewer('an HTML previewer', ['xdg-open', 'firefox', 'mozilla file://$$p$$i', 'netscape'],
         rc_entry = [r'\Format xhtml      xhtml   "LyXHTML"              y "%%" ""    "document,menu=export"	"application/xhtml+xml"'])
  #
     checkEditor('a BibTeX editor', ['jabref', 'JabRef', \
@@ -646,14 +646,14 @@
     #
     #checkProg('a Postscript interpreter', ['gs'],
     #  rc_entry = [ r'\ps_command "%%"' ])
-    checkViewer('a Postscript previewer', ['kghostview', 'okular', 'evince', 'gv', 'ghostview -swap'],
+    checkViewer('a Postscript previewer', ['xdg-open', 'kghostview', 'okular', 'evince', 'gv', 'ghostview -swap'],
         rc_entry = [r'''\Format eps        eps     EPS                    "" "%%"	""	"vector"	"image/x-eps"
 \Format eps2       eps    "EPS (uncropped)"       "" "%%"	""	"vector"	""
 \Format eps3       eps    "EPS (cropped)"         "" "%%"	""	"document,menu=export"	""
 \Format ps         ps      Postscript             t  "%%"	""	"document,vector,menu=export"	"application/postscript"'''])
     # for xdg-open issues look here: http://www.mail-archive.com/lyx-devel@lists.lyx.org/msg151818.html
     # the MIME type is set for pdf6, because that one needs to be autodetectable by libmime
-    checkViewer('a PDF previewer', ['pdfview', 'kpdf', 'okular', 'evince', 'kghostview', 'xpdf', 'acrobat', 'acroread', 'mupdf', \
+    checkViewer('a PDF previewer', ['xdg-open', 'pdfview', 'kpdf', 'okular', 'evince', 'kghostview', 'xpdf', 'acrobat', 'acroread', 'mupdf', \
 		    'gv', 'ghostview'],
         rc_entry = [r'''\Format pdf        pdf    "PDF (ps2pdf)"          P  "%%"	""	"document,vector,menu=export"	""
 \Format pdf2       pdf    "PDF (pdflatex)"        F  "%%"	""	"document,vector,menu=export"	""
@@ -663,14 +663,14 @@
 \Format pdf6       pdf    "PDF (graphics)"        "" "%%"	""	"vector"	"application/pdf"
 \Format pdf7       pdf    "PDF (cropped)"         "" "%%"	""	"document,menu=export"	""'''])
     #
-    checkViewer('a DVI previewer', ['xdvi', 'kdvi', 'okular', 'yap', 'dviout -Set=!m'],
+    checkViewer('a DVI previewer', ['xdg-open', 'xdvi', 'kdvi', 'okular', 'yap', 'dviout -Set=!m'],
         rc_entry = [r'''\Format dvi        dvi     DVI                    D  "%%"	""	"document,vector,menu=export"	"application/x-dvi"
 \Format dvi3       dvi     "DVI (LuaTeX)"          V  "%%"	""	"document,vector,menu=export"	""'''])
     if dtl_tools:
         # Windows only: DraftDVI
         addToRC(r'\Format dvi2       dvi     DraftDVI               ""	""	""	"vector"	""')
     #
-    checkViewer('an HTML previewer', ['firefox', 'mozilla file://$$p$$i', 'netscape'],
+    checkViewer('an HTML previewer', ['xdg-open', 'firefox', 'mozilla file://$$p$$i', 'netscape'],
         rc_entry = [r'\Format html      "html, htm" HTML                H  "%%"	""	"document,menu=export"	"text/html"'])
     #
     checkViewerEditor('Noteedit', ['noteedit'],