KenViet,
There is a function called �GetRelativeMouseState()� that returns the location of the mouse relative to a specific control:
int GetRelativeMouseState (int panelHandle, int controlID, int *xCoordinate, int *yCoordinate, int *leftButtonDown, int *rightButtonDown, int *keyModifiers);
To find out more about this function go to Help->Contents and click on the �Index� tab and type �GetRelativeMouseState()�. I hope that function does the trick for you. If not please post again. Good luck!
Craig H.
National Instruments