Hi Ell,
This can be caused by the fact that the control does not process some standard Windows messages properly. I would really appreciate it if you sent me a simple application containing the problematic control (not the application you are testing). If you cannot do this, please answer the following questions so I can help you:
1. What is the value of the control's WndClass property (you can check it using the Object Browser)? If the control is a .NET control, please tell me the value of its ClrFullClassName property.
2. What is the name of the component used to implement the control?
3. What language and IDE were used to create the application?
Also, if the control is not a standard one, let me know its vendor and version.
Thanks in advance.