To reproduce: 1. Drag and drop RadPageView on the form 2. Add 2-3 pages 3. Set the ViewType to Backstage 4. Open smart tag and press Delete key to edit the Item Area Width property. After pressing the key, the RadPageView is removed from form. The issue is observed in Visual Studio 2015 only.
The issue is introduced by Visual Studio 2015. You can track its progress on Visual Studio`s feedback page on the following link: https://connect.microsoft.com/VisualStudio/feedback/details/2012566