Keep track of the area intended to be buffered, and use that in UnMask instead of defaulting to the buffer size. Only clip to the DC size if wxBUFFER_VIRTUAL_AREA is not set. This fixes the issue where buffering the full virtual area in a wxScrolledWindow would only draw an area the physical size of the window. Fixes #11612.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@71704 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/dcbuffer.h

@@ -134,6 +134,8 @@ private:
     // the buffering style
     int m_style;
 
+    wxSize m_area;
+    
     DECLARE_DYNAMIC_CLASS(wxBufferedDC)
     wxDECLARE_NO_COPY_CLASS(wxBufferedDC);
 };