Since the dummy actor occupies exactly the same area of the Hot Corner,
it can be erroneously picked during xdnd operations. Fix this by
hiding it from pick.
https://bugzilla.gnome.org/show_bug.cgi?id=669831
// Used as a drag actor in case we don't have a cursor window clone
this._dummy = new Clutter.Rectangle({ width: 1, height: 1, opacity: 0 });
global.stage.add_actor(this._dummy);
+ Shell.util_set_hidden_from_pick(this._dummy, true);
this._dummy.hide();
// Mutter delays the creation of the output window as long