Thank you for your reply.
As I mentioned, the control that you call menu is a RadTreeView control with some formatting on it. Feel free to review the link provided in my previous post regarding this control.
In regards to the expandable menu which you mentioned, this is an expander which is not part of our suite and we do not officially support is. It is created with our Telerik Presentation Framework for the purposes of our examples. In the attached project, you can find a stripped version of this splitter. Feel free to modify it according to your needs.
Since you are a customer, you will be able to download our source code. If you do so, you can find the whole demo application code in \Examples folder.
I hope that the provided information addresses your questions. Let me know if I can be of further assistance.
All the best,
the Telerik team