The framework calls this member function by a minimized (iconic) window that does not have an icon defined for its class.
The system makes this call to obtain the cursor to display while the user drags the minimized window. If an application returns the handle of an icon or cursor, the system converts it to black-and-white. If an application returns a handle, the handle must identify a monochrome cursor or icon compatible with the display driver's resolution. The application can call the CWinApp::LoadCursor or CWinApp::LoadIcon member functions to load a cursor or icon from the resources in its executable file and to obtain this handle.