1. always create the buttons with WS_CLIPSIBLINGS style, this prevetns them

from overwriting each other when the main window is resized
2. more tweaks to MSWGetStyle() and related code, added a new, easier to use,
   version of MSWCreateControl()


git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@14313 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/msw/window.cpp

@@ -1027,7 +1027,11 @@ void wxWindowMSW::SetWindowStyleFlag(long flags)
     // update the internal variable
     wxWindowBase::SetWindowStyleFlag(flags);
 
-    // now update the Windows style as well if needed
+    // now update the Windows style as well if needed - and if the window had
+    // been already created
+    if ( !GetHwnd() )
+        return;
+
     WXDWORD exstyle, exstyleOld;
     long style = MSWGetStyle(flags, &exstyle),
          styleOld = MSWGetStyle(flagsOld, &exstyleOld);