http://blogs.msdn.com/b/zainnab/archive/2012/06/19/visual-studio-2012-new-features-preview-tab.aspx
In Q3 2015 we will add new feature - preview tab in RadDock and RadPageView. You can use the following code snippet: 1. For RadDock documentWindow1.TabStrip.TabStripElement.PreviewItem = documentWindow1.TabStripItem; 2. For RadPageView (radPageView1.ViewElement as RadPageViewStripElement).PreviewItem = radPageViewPage1.Item;