I tested the provided code with some modifications (as in the code from your post there are some missing classes such as Tools, etc.) but was not able to reproduce the problem. I suggest that you try to isolate the problem in a small running
project and send it to us so we can run it and reproduce the issue. Please, include the bin folder and all necessary files and folders too. To be able to attach file to your thread you need to open a support ticket as described in the attached instructions.
All the best,
the Telerik team