I used SetCursor(LoadCursor(NULL, IDC_WAIT)) to change my cursor and like what it says in MSDN: "If your application must set the cursor while it is in a window, make sure the class cursor for the specified window's class is set to NULL. If the class cursor is not NULL, the system restores the class cursor each time the mouse is moved. " But how can I set the window's class cursor to NULL? Can anyone give me a hint? Thanks.