Hi Makla,
It is as Dimitar, says. It is event bubbling. Both jqxtabs and jqxwindow have an event called “created” which means that when you subscribe to the top DIV tag – the jqxWindow, you will listen for the jqxTabs and jqxWindow “created” event. Well, both these widgets raise their event and that is the reason why you have 2 alerts. It’s simple and is called Event Bubbling – the jqxTabs “created” event bubbles up to the jqxWindow which listens for the “created” event..
Best Regards,
Peter Stoev
jQWidgets Team
http://www.jqwidgets.com