Bug#934385: wxDC::Clear() doesn't work if wxWidgets uses GTK3

[Gunter Königsmann]

Package: libwxgtk3.0-gtk3-0v5
Version: 3.0.4+dfsg-9

If a draw context is used and wxWidgets 3.0 (3.1 isn't affected, but isn't 
packaged with debian as it is the development version) uses GTK3 the background 
is likely not to be cleared before a redraw as wxDC::Clear() doesn't work under 
these circumstances.