sync when killing all keyboard grabs, so that we can be sure they are gone before proceeding (fixes a race condition when running things that want to grab the keyboard very quickly. yes, arch is that fast somehow..)

openbox/event.c

@@ -1997,6 +1997,8 @@ void event_cancel_all_key_grabs(void)
     }
     else
         ungrab_passive_key();
+
+    XSync(ob_display, FALSE);
 }
 
 gboolean event_time_after(Time t1, Time t2)