Linux: update xdg-utils again, and check in the built versions of the scripts.

scripts/xdg-email

 #!/bin/sh
 #---------------------------------------------
 #   xdg-email
 #
 #   Utility script to open the users favorite email program, using the
 #       RFC 2368 mailto: URI spec
 #
 #   Refer to the usage() function below for usage.
 #
 #   Copyright 2009-2010, Fathi Boudra <fabo@freedesktop.org>
@@ skipping 342 matching lines @@
 #--------------------------------------
 # Checks for known desktop environments
 # set variable DE to the desktop environments name, lowercase
 
 detectDE()
 {
     if [ x"$KDE_FULL_SESSION" = x"true" ]; then DE=kde;
     elif [ x"$GNOME_DESKTOP_SESSION_ID" != x"" ]; then DE=gnome;
     elif `dbus-send --print-reply --dest=org.freedesktop.DBus /org/freedesktop/DBus org.freedesktop.DBus.GetNameOwner string:org.gnome.SessionManager > /dev/null 2>&1` ; then DE=gnome;
     elif xprop -root _DT_SAVE_MODE 2> /dev/null | grep ' = \"xfce4\"$' >/dev/null 2>&1; then DE=xfce;
-    elif [ x"$DESKTOP_SESSION" == x"LXDE" ]; then DE=lxde;
-    else DE=""
+    fi
+
+    if [ x"$DE" = x"" ]; then
+      # fallback to checking $DESKTOP_SESSION
+      case "$DESKTOP_SESSION" in
+         LXDE)
+           DE=lxde; 
+           ;;
+         xfce|xfce4)
+           DE=xfce;
+           ;;
+      esac
+    fi
+
+    if [ x"$DE" = x"" ]; then
+      # fallback to uname output for other platforms
+      case "$(uname 2>/dev/null)" in 
+        Darwin)
+          DE=darwin;
+          ;;
+      esac
+    fi
+
+    if [ x"$DE" = x"gnome" ]; then
+      # gnome-default-applications-properties is only available in GNOME 2.x
+      # but not in GNOME 3.x
+      which gnome-default-applications-properties 2> /dev/null || DE="gnome3"
     fi
 }
 
 #----------------------------------------------------------------------------
 # kfmclient exec/openURL can give bogus exit value in KDE <= 3.5.4
 # It also always returns 1 in KDE 3.4 and earlier
 # Simply return 0 in such case
 
 kfmclient_fix_exit_code()
 {
@@ skipping 91 matching lines @@
     LC_ALL=C.UTF-8 $KMAILSERVICE "$1"
     kfmclient_fix_exit_code $?
 
     if [ $? -eq 0 ]; then
         exit_success
     else
         exit_failure_operation_failed
     fi
 }
 
+open_gnome3()
+{
+    local client
+    local desktop
+    desktop=`xdg-mime query default "x-scheme-handler/mailto"`
+    client=`desktop_file_to_binary "$browser"`
+    echo $client | grep thunderbird > /dev/null 2>&1
+    if [ $? -eq 0 ] ; then
+        run_thunderbird "$client" "$1"
+    fi
+
+    if gvfs-open --help 2>/dev/null 1>&2; then
+        DEBUG 1 "Running gvfs-open \"$1\""
+        gvfs-open "$1"
+    else
+        DEBUG 1 "Running gnome-open \"$1\""
+        gnome-open "$1"
+    fi
+
+    if [ $? -eq 0 ]; then
+        exit_success
+    else
+        exit_failure_operation_failed
+    fi
+}
+
 open_gnome()
 {
     local client
     client=`gconftool-2 --get /desktop/gnome/url-handlers/mailto/command | cut -d ' ' -f 1` || ""
     echo $client | grep thunderbird > /dev/null 2>&1
     if [ $? -eq 0 ] ; then
         run_thunderbird "$client" "$1"
     fi
 
     if gvfs-open --help 2>/dev/null 1>&2; then
@@ skipping 220 matching lines @@
 
 case "$DE" in
     kde)
     open_kde "${mailto}"
     ;;
 
     gnome)
     open_gnome "${mailto}"
     ;;
 
+    gnome3)
+    open_gnome3 "${mailto}"
+    ;;
+
     xfce)
     open_xfce "${mailto}"
     ;;
 
     generic|lxde)
     open_generic "${mailto}"
     ;;
 
     *)
     exit_failure_operation_impossible "no method available for opening '${mailto}'"
     ;;
 esac