P2,
Are you developing an MFC application or a standard Win32 project? For an MFC application, the project should automatically be set up to handle messages which would respond to your UI interactions. For a Win32 application, you must ensure that you have a message dispatch loop. The following link has a good description of the Message Loop:
http://www.winprog.org/tutorial/message_loop.html
It may be that you are performing some operation that takes a very long time so the Message Loop handling (either in the MFC or Win32 app) is not being called often enough. In that case, you must see if it is possible to break up your operations so that the Mesasge Loop is still handled. A good way to take care of this is to fork a separate thread for the heavy operations to take place in.
If this is not related to the use of Measurement Studio controls, you may get a better or more detailed answer if you post this question on a generic Windows programming forum.
Thanks,
Tyler Tigue
Applications Engineer
National Instruments