zk.afterLoad('zul.menu', function() {
		var xMenupopup = {};
		zk.override(zul.menu.Menupopup.prototype, xMenupopup, {
			open : function (ref, offset, position, opts) {
				if(!offset && !position) {
					this._reverseDir = this._parentPopup()._reverseDir || false;
					if(this._reverseDir) position = 'start_before';
				}
				xMenupopup.open.call(this, ref, offset, position, opts);
			},
			_syncPos : function () {
				var parentPopup = this._parentPopup();
				if(parentPopup && zk(this).isOverlapped(parentPopup.$n(), 5)) {
					this._reverseDir = !this._reverseDir;
					var position = this._reverseDir ? 'start_before' : 'end_before';
					zk(this).position(this.parent.$n().getBoundingClientRect(), position, {})
				}
			},
			_parentPopup : function () {
				return jq(this.parent).closest('@menupopup').zk.$();
			}

		});//zk.override
	});//zk.afterLoad