use a single wxBookCtrlEvent class for all wxBookCtrlBase-derived controls (#9667)

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@54895 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/generic/mdig.cpp

@@ -775,7 +775,7 @@ void wxGenericMDIClientWindow::PageChanged(int OldSelection, int newSelection)
     }
 }
 
-void wxGenericMDIClientWindow::OnPageChanged(wxNotebookEvent& event)
+void wxGenericMDIClientWindow::OnPageChanged(wxBookCtrlEvent& event)
 {
     PageChanged(event.GetOldSelection(), event.GetSelection());