Menu: Check that there is an active item in `_activate()`

Closes gh-1606

diff --git a/ui/widgets/menu.js b/ui/widgets/menu.js
index c5627cc20713ef93c5796cfbb8113eb94542307d..f63105fa771004e984b48a3e4e47b8fbfa0bffa7 100644 (file)
--- a/ui/widgets/menu.js
+++ b/ui/widgets/menu.js
@@ -270,7 +270,7 @@ return $.widget( "ui.menu", {
        },
 
        _activate: function( event ) {
-               if ( !this.active.is( ".ui-state-disabled" ) ) {
+               if ( this.active && !this.active.is( ".ui-state-disabled" ) ) {
                        if ( this.active.children( "[aria-haspopup='true']" ).length ) {
                                this.expand( event );
                        } else {