Created Issue: TabPanels being duplicated in designview [27230]

This happens when I make any changes in the Properties window of any control I have placed in any of the tabpanels.

ajaxcontroltoolkit ver: 4.1.60623.0
Microsoft Visual Studio 2010 : Version 10.0.40219.1 SP1Rel
Microsoft .NET Framework: Version 4.0.30319 SP1Rel