Also fix a minor zoom page issue in Libedit.
wxMSW, version 2.8.x must be patched.
Some zoom values smaller than 3 to 5 create artifacts on screen, mainly values < 1.
(corresponding to draw scale factor > 1 )

 * see http://trac.wxwidgets.org/ticket/9554
 
This is fixed in version 2.9.x
Workaround: ( that is not a full fix, but remaining artifacts are acceptable )
edit file  edit file <wxWidgets>/src/msw/dc.cpp
 >> search for line
    static const int VIEWPORT_EXTENT = 1000;
 >> and replace by
    static const int VIEWPORT_EXTENT = 10000;