Problems with snapping to segments

[wonder-sk]

1. When starting to trace on segment, it works properly only if the endpoint is a vertex.
2. autotrace seems to ignore first(?) point of the geometry when tracing from first(?) segment

[tobias47n9e]

I tried around a bit to find the issue behind my feeling that the plugin is somehwat 'unstable' or 'random' in its behavior. I think now that it is actually my snapping options were set to vertex + line instead of just vertex. On the other hand it would be nice if the plugin could also work from line to line instead of just vertex to vertex.