Setting the style mask does not affect the windows layout as it should

The change in 3276cca0 that fixed a bug related to setting the window's style mask was preventing the window's layout from being properly updated.  One way this manifests itself is if a window needs to flip back and forth from having a titlebar and not having a titlebar.  When going from not having a title bar to having a title bar by setting the style mask, the window would resize it's content view correctly but the title bar area would just be a white rectangle.