gistfile1.txt

    changeGroup: function changeGroup(TargetGroupTitle){
        let activeTab = window.gBrowser.selectedTab;

        let targetGroupId = this.getIdByTitle(TargetGroupTitle);
            
        if (targetGroupId != null){
            TabView.moveTabTo(activeTab, targetGroupId);
            TabView.hide();
        }
        
        activeTab._tabViewTabItem.parent.closeIfEmpty()
    }