I get the same behaviour noted by Patrick - the previously selected tab index is returned, not the just-selected one.
Kiril, I've adapted your dojo example to demonstrate the behaviour here: http://dojo.telerik.com/UkUHi
The main difference is that I've added an onSelect event and tried to get the tabstrip.select().index() from there. Note also that I changed the Kendo js/css to a more recent version from the CDN.
Any clues or solution anyone?