I have an MDI application and would like to add tabs to the MainFrame (the CMDIFrameWnd derived class) so that the child windows are added to the tab control without losing the other MDI functionality (cascade, tile, etc). This would create a "workbook" feel in the MDI application. The tabs would act just like selcting a child window from the "Window" menu. I've tried changing the window class to "SysTabControl32" in the CREATESTRUCT but have had no luck. Has anyone tried this or have any ideas? I've been told that there are some software packages available that can extend MFC in this manner, unfortunately my funds are very limited. Thanks for any help.