I now have a working polyline, though with a few bugs left. Worst is that
the display doesn't get updated when adding/removing points via the object
menu. I do a ddisplay_flush() on the active display after the callback is
done, but that isn't enough. I guess there's a magic function call
somewhere I haven't found.
I'm not quite happy with the interface, though. It would be nicer to add
points like in xfig, where you just click the whole polyline out. I don't
see a way to do that here that fits with the rest of the interface.
-Lars
