merged NULL wxFrame parent HWND fix from 2.2 branch

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@11049 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/msw/frame.cpp

@@ -156,6 +156,14 @@ bool wxFrameMSW::Create(wxWindow *parent,
 
   m_iconized = FALSE;
 
+  // the frame must have NULL parent HWND or it would be always on top of its
+  // parent which is not what we usually want (in fact, we only want it for
+  // frames with the special wxFRAME_FLOAT_ON_PARENT style)
+  if ( !(m_windowStyle & wxFRAME_FLOAT_ON_PARENT) )
+  {
+    parent = NULL;
+  }
+
   wxTopLevelWindows.Append(this);
 
   MSWCreate(m_windowId, parent, wxFrameClassName, this, title,