Found by testing for #1658 with:
check_randr_sizes
opengl=no
With python2, the rendering is broken, with python3 the client crashes!
r19645 adds better debug logging.
The problem seems to come from relative vs absolute coordinates: some methods call queue_draw
with relative coordinates, others expect it to honour absolute coordinates and repaint the whole window, including the padding area..
Large fix in r19647, also fixes the crashes with python3. (looks like cairo / python3 doesn't do enough validation and just crashes... python2 just renders junk?)
queue_draw
is part of the GTK API, we should always use absolute window coordinates there.
Other related changesets:
r19647 caused a regression: ticket:1339#comment:35.
this ticket has been moved to: https://github.com/Xpra-org/xpra/issues/1874