I have added a NI measurement studio GRAPH contrl into a VC++6.0 dialog(MyDialog). In the function "CMyDialog::OnSize(...)",I altered the contrl's Width and Height attribute. Now, the application is running , and MyDialog is active window. When I LButtonDown the GRAPH contrl region,it's Width and Height value come back to the original value befor I altered in "CMyDialog::OnSize(...)". But if the contrl has the current focus,the problem not happen. MyDialog has some other Buttons,so I am not able to assure the contrl has the focus all the time . How can I solve the problem?