missing return value

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@64048 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/osx/window_osx.cpp

@@ -139,6 +139,7 @@ public:
         
         // so that non-solid background renders correctly under GTK+:
         SetThemeEnabled(true);
+        return true;
     }
     
     virtual ~wxBlindPlateWindow();