I just downloaded the latest production version and upgraded my project and have run into manu issues within 2 min of running my application. On the tabcontrol, the selected item is behaving differently.  If you run your databinding example for the tab control and use the "x" to close the tabs you'll notice there is no selected item afterwards.  If you run the 2010 demo it works fine.  I am using Prism and MVVM and have a solution that works with the 2010 Q3 release but now does not work now that I have upraded (similar to how I explained it worked in your demo).

Hi Heather,

This is a bug in the Q1 2011 RadTabControl. We logged it in our PITS (TabControl: When removing the selected tab dynamically,then no tab is getting selected) where you will be soon able to track its status. We also updated your telerik account points.Thank you for your cooperation.

Regards,
Petar Mladenov
the Telerik team

Hi Heather,

We want to inform you, that this issue is already fixed.
You can check it in our next internal build. It should be released in the beginning of the next week.
Any feedback/comments on the subject (once the internal build is available) are highly appreciated.

All the best,
Vladislav
the Telerik team