afx_msg BOOL OnQueryOpen();
Called when the CWnd is iconized and the user requests that the CWnd be opened into a window.
While in OnQueryOpen, CWnd should not perform any action that would cause an activation or focus change (for example, creating a dialog box).
This message-handler member function calls the Default member function. Override this member function in your derived class to handle the WM_QUERYOPEN message.
TRUE if the icon can be opened, or FALSE to prevent the icon from being opened.
CWnd::Default, WM_QUERYOPEN