wxRadioButton works under MSW

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/branches/wxUNIVERSAL@8321 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/univ/renderer.cpp

@@ -441,6 +441,7 @@ void wxControlRenderer::DrawBitmap(const wxBitmap& bitmap,
         {
             for ( y = 0; y < rect.height; y += height )
             {
+                // no need to use mask here as we cover the entire window area
                 m_dc.DrawBitmap(bmp, x, y);
             }
         }