In procedure PrecreateWindow() of CMainFrame I changed the class name for my main frame window of my application something like this:
BOOL CMainFrame::PreCreateWindow(CREATESTRUCT& cs)
myclass.lpszClassName = "MyApplication";
and so on ...
What now happens is that the icon in the upper left corner of my main frame window disappeared. What can cause that and how can I repair it, that my icon is appearing again ?