Comment 5 for bug 537619

I can reproduce this bug outside of Pitivi. This looks like a subtlety/bug in pygtk!

In pygtk02.17.0/gtk/gdkcairo.override, lines 128 to 144, the wrapper requests keyword arguments "cr" and "drawable". Most other wrappers seem not to use the "cr" arguments, but retrieve the cairo context by using PycairoContext_GET(self). Maybe we just want to push this upstream and ask the pygtk developers what was their idea... In any case, gtk.gdk.CairoContext.reset_clip is undocumented.

A solution (or workaround, depending on how we perceive this) would be to replace

    cr.reset_clip()

with

    cr.reset_clip(cr=cr, drawable=self.get_canvas())