[Inkscape-devel] tracing bitmap images using bucket tool

hi everyone, I used to selectively trace bitmap images using bucket tool, and I think it is a great feature and a wonderful trick in my workflow. Now I've compiled a fresh source from bzr, and tracing bitmaps this way seems not working anymore, I get only a message of non-closed surface or something similar.

has this feature been removed on purpose, or am I somehow facing a bug?

best to all, francesco