diff -urp webkitgtk-2.28.0.orig/Source/WebKit/UIProcess/API/glib/WebKitWebContext.cpp webkitgtk-2.28.0/Source/WebKit/UIProcess/API/glib/WebKitWebContext.cpp
--- webkitgtk-2.28.0.orig/Source/WebKit/UIProcess/API/glib/WebKitWebContext.cpp	2020-02-04 04:30:36.000000000 -0600
+++ webkitgtk-2.28.0/Source/WebKit/UIProcess/API/glib/WebKitWebContext.cpp	2020-03-19 14:16:07.742318092 -0500
@@ -379,8 +379,16 @@ static void webkitWebContextConstructed(
     configuration.setProcessSwapsOnNavigation(priv->psonEnabled);
     if (!priv->psonEnabled) {
         const char* useSingleWebProcess = getenv("WEBKIT_USE_SINGLE_WEB_PROCESS");
-        if (useSingleWebProcess && strcmp(useSingleWebProcess, "0"))
-            configuration.setUsesSingleWebProcess(true);
+        if (useSingleWebProcess) {
+            if (strcmp(useSingleWebProcess, "0")) {
+                configuration.setUsesSingleWebProcess(true);
+            }
+        } else {
+            const char* prgname = g_get_prgname();
+            if (!g_strcmp0(prgname, "evolution") || !g_strcmp0(prgname, "geary")) {
+                configuration.setUsesSingleWebProcess(true);
+            }
+        }
     }
 #endif