Try this approach for now:
...
if llist<>'' then
begin
//MyTreeMenu.JSInterface.JSAssign('_rtext', [MyTreeMenu.JSControl.JSArray(llist)]);
MyTreeMenu.JSInterface.JSAssign('_rtext', [MyTreeMenu.JSInterface.JSStatement('[' + llist + ']')]);
MyTreeMenu.JSInterface.JSCode('var me='#1';'+
'if(me._rtext) me.getStore().each(function(record) {'+
' if (me._rtext.indexOf(record.get("text")) > -1) {'+
' record.remove()'+
' }'+
'});'
);
end;
...