destroy the old clipping region before setting the new one (part of patch 1716763)

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@48720 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/univ/textctrl.cpp

@@ -4193,6 +4193,7 @@ void wxTextCtrl::DoDraw(wxControlRenderer *renderer)
     // FIXME: is this really a bug in wxMSW?
     rectTextArea.width--;
 #endif // __WXMSW__
+    dc.DestroyClippingRegion();
     dc.SetClippingRegion(rectTextArea);
 
     // adjust for scrolling