[gnome-shell] panel: Don't try to begin a grab op while something else has taken a grab

[Jasper St. Pierre <jstpierre src gnome org>]

commit 3db253998b18b13cf84f637d148f642c5d379a3f
Author: Jasper St. Pierre <jstpierre mecheye net>
Date:   Tue Feb 19 20:27:11 2013 -0500

    panel: Don't try to begin a grab op while something else has taken a grab
    
    https://bugzilla.gnome.org/show_bug.cgi?id=694241

 js/ui/panel.js |    3 +++
 1 files changed, 3 insertions(+), 0 deletions(-)
---
diff --git a/js/ui/panel.js b/js/ui/panel.js
index 7153abd..f24f3a4 100644
--- a/js/ui/panel.js
+++ b/js/ui/panel.js
@@ -1065,6 +1065,9 @@ const Panel = new Lang.Class({
     },
 
     _onButtonPress: function(actor, event) {
+        if (Main.modalCount > 0)
+            return false;
+
         if (event.get_source() != actor)
             return false;