good point, I've done this - and it works just like the real thing. I'm leaving my upvote here not because I need this feature anymore, but because it could improve smartgit for other me's in future, to have it directly in the GUI

Often after checking out a divergent branch and rebuilding my project, I have to manually do git clean, then re-buildout the project. I would love an option for "clean on branch checkout" to prevent this minor irritation!