Thank you for contacting us about this issue. In general, we are aware about it, although until the time present we were unable to reproduce it consistently and to isolate what causes it. In each of the known cases, resetting the Toolbox window solves the visual problem without further complications.
In this connection, could you right-click on any of the sections in Toolbox and select the Reset Toolbox option?
If the problem starts to appear again, could you provide us with environment details like, the specific version of Visual Studio 2013 you use, the version of the .NET Framework, OS on your side, list of installed products in Visual Studio?
Let us know how the things are on your side.
OpenAccess ORM is now Telerik Data Access
. For more information on the new names, please, check out the Telerik Product Map