1. wxWindow::Centre() hopefully fixed

2. attempts to construct bitmaps from icons properly
3. wxTreeCtrl background is always white


git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@3232 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/msw/dc.cpp

@@ -591,6 +591,9 @@ void wxDC::DoDrawBitmap( const wxBitmap &bmp, long x, long y, bool useMask )
         HDC cdc = GetHdc();
         HDC memdc = ::CreateCompatibleDC( cdc );
         HBITMAP hbitmap = (HBITMAP) bmp.GetHBITMAP( );
+
+        wxASSERT_MSG( hbitmap, _T("bitmap is ok but HBITMAP is NULL?") );
+
         ::SelectObject( memdc, hbitmap );
         ::BitBlt( cdc, x, y, bmp.GetWidth(), bmp.GetHeight(), memdc, 0, 0, SRCCOPY);
         ::DeleteDC( memdc );