CWnd::LockWindowUpdate
BOOL LockWindowUpdate( );
Return Value
Nonzero if the function is successful. It is 0 if a failure occurs or if the LockWindowUpdate function has been used to lock another window.
Remarks
Disables drawing in the given window. A locked window cannot be moved. Only one window can be locked at a time. To unlock a window locked with LockWindowUpdate, call UnlockWindowUpdate.