There is a BUG with calling enable() or disable() methods when enableGroupingMenu=false

Uncaught TypeError: Cannot call method 'setChecked' of null

Code:
disable: function() {
        var me    = this,
            view  = me.view,
            store = view.store,
            remote = store.remoteGroup,
            groupToggleMenuItem,
            lastGroup;


        lastGroup = store.groupers.first();
        if (lastGroup) {
            me.lastGroupIndex = lastGroup.property;
            me.block();
            store.clearGrouping();
            me.unblock();
        }


        me.callParent();
        groupToggleMenuItem = me.view.headerCt.getMenu().down('#groupToggleMenuItem');
        groupToggleMenuItem.setChecked(true, true); <--Uncaught TypeError: Cannot call method 'setChecked' of null



        groupToggleMenuItem.setChecked(false, true);
        if (!remote) {
            view.refresh();        
        }
    },

Variable "groupToggleMenuItem" is null when enableGroupingMenu=false. Should be checked before call setChecked