diff -Nru metacity-2.34.13/debian/changelog metacity-2.34.13/debian/changelog
--- metacity-2.34.13/debian/changelog	2014-02-13 13:26:19.000000000 +0000
+++ metacity-2.34.13/debian/changelog	2015-04-26 16:21:57.000000000 +0000
@@ -1,3 +1,10 @@
+metacity (1:2.34.13-0ubuntu4.1) trusty; urgency=medium
+
+  * Backport upstream patch to not grab keybindings without modmask
+    (LP: #1440570, thanks to Alberts Muktupāvels).
+
+ -- Marc Deslauriers <marc.deslauriers@ubuntu.com>  Sun, 26 Apr 2015 12:21:17 -0400
+
 metacity (1:2.34.13-0ubuntu4) trusty; urgency=low
 
   * debian/patches/22_fix_above_tab_switching.patch:
diff -Nru metacity-2.34.13/debian/patches/require_modmask.patch metacity-2.34.13/debian/patches/require_modmask.patch
--- metacity-2.34.13/debian/patches/require_modmask.patch	1970-01-01 00:00:00.000000000 +0000
+++ metacity-2.34.13/debian/patches/require_modmask.patch	2015-04-26 16:21:12.000000000 +0000
@@ -0,0 +1,24 @@
+Description: keybindings: don't grab keybindings without modmask
+Origin: upstream, https://git.gnome.org/browse/metacity/commit/?id=5aeae2fcc6763839
+Last-Update: 2015-04-09
+
+Index: metacity-2.34.13/src/core/keybindings.c
+===================================================================
+--- metacity-2.34.13.orig/src/core/keybindings.c	2015-04-26 12:21:10.096479979 -0400
++++ metacity-2.34.13/src/core/keybindings.c	2015-04-26 12:21:10.092479946 -0400
+@@ -685,6 +685,15 @@
+    * X provides no better way to do this.
+    */
+ 
++  if (modmask == 0)
++    {
++      meta_topic (META_DEBUG_KEYBINDINGS,
++                  "Will not %s keybinding %s without modmask\n",
++                  grab ? "grab" : "ungrab",
++                  keysym_name (keysym));
++      return;
++    }
++
+   meta_topic (META_DEBUG_KEYBINDINGS,
+               "%s keybinding %s keycode %d mask 0x%x on 0x%lx\n",
+               grab ? "Grabbing" : "Ungrabbing",
diff -Nru metacity-2.34.13/debian/patches/series metacity-2.34.13/debian/patches/series
--- metacity-2.34.13/debian/patches/series	2014-02-13 13:26:19.000000000 +0000
+++ metacity-2.34.13/debian/patches/series	2015-04-26 16:21:08.000000000 +0000
@@ -24,3 +24,4 @@
 #19_add_unity_hud_configuration.patch
 #101_override_gconf_settings.patch
 22_fix_above_tab_switching.patch
+require_modmask.patch