I have a master page that contains a radMenu. On another page, which uses this master page, my content contains a radPanelBar with various radPanelItems (links mostly) and then a radTabStrip. Inside those tabs our pageViews with radGrids and other content.
So you have on the left side of the screen a menu, then a panel bar to the right of that. Then to the right of that a tab strip with it's PageView content displayed based on whichever tab is currently active.
The issue I'm seeing once I installed the new version of Telerik's controls is that the controls are laying on top of each other. The radPanelBar, instead of appearing to the right of the radMenu is actually underneath it. The tab strip is off to the right but the header of the page is over laying the menu as well. So all the positioning of all the rad controls is completely messed up. I'm just reporting this as a caution. The solution was easy. Just don't use the latest version of the Telerik controls. I could have posted the code but it would have been quite lengthy and I think with this you could replicate a test scenario using master pages with a Panel Bar and TabStrip.