Distribution/Version: ubuntu hoary

Steps to reproduce bug:

1. Choose "Save" from a GNOME/GTK application
2. Type Alt-B to open the "Browse for other folders..." expander
3. Start typing name of folder I want to browser to.
4. Discover focus has not moved! Alas, I'm typing over my file name.

Expected behavior: 
The focus should move to the treeview of filenames (on the righthand side) when
I expand the browse widget. It should go there (and not to the bookmarks on the
left) since I could access the bookmarked folders more quickly by typing "Alt-F"
and seeing the folders.

Further confusion is caused by the folder selector being desensitized.  Why
can't I use this convenient menu bar anymore? If I change my mind and decide I
want a bookmarked folder after all, I no longer have a fast keyboard way to do
so (Alt-f + arrows).

This is all a special case of a more generic bug in the file selector: there are
no mnemonics to allow me to get quickly to the treeview showing the current
directory. This is a problem because there are so many controls in the view that
tabbing between e.g. the filename and the view is not efficient as it was, say,
in the Mac OS 8 file selector.