After having a discussion a while back with Greg, I decided to try to re-implement a golden oldy. Namely the ‘breadcrumb’ bar and artist search in the metdata browser.
The current metadata browser forces you to use the 3 panes on the left to browse through your collection, this is not always the best/easiest way.

So, in very little code, I re-introduced the old bread-crumb bar:

old:

Now:

And a video of the bar and history system in action: mb-grf.ogv

You can test it using the metadata-gregf branch, feedback is welcome.