commit bf2829371c874c0c29d92a1bd979a97a345a9a68
Author: Changwoo Ryu <cwryu@debian.org>
Date:   Sat May 3 02:50:06 2014 +0900

    Allow input of Hangul and Shift+Space shortcuts
    
    They are commonly used for Korean Hangul keyboard toggle, input-source-switch.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=729419

diff --git a/src/core/prefs.c b/src/core/prefs.c
index ac76130..01f71a5 100644
--- a/src/core/prefs.c
+++ b/src/core/prefs.c
@@ -1922,11 +1922,15 @@ update_binding (MetaKeyPref *binding,
 
       /* Bug 329676: Bindings which can be shifted must not have no modifiers,
        * nor only SHIFT as a modifier.
+       *
+       * Exceptions are Shift+Space and Hangul which are being used for
+       * switch-input-source shortcut.
        */
 
       if (binding->add_shift &&
           0 != keysym &&
-          (META_VIRTUAL_SHIFT_MASK == mods || 0 == mods))
+          ((META_VIRTUAL_SHIFT_MASK == mods && GDK_KEY_space != keysym) ||
+           (0 == mods && GDK_KEY_Hangul != keysym)))
         {
           meta_warning ("Cannot bind \"%s\" to %s: it needs a modifier "
                         "such as Ctrl or Alt.\n",
