When you decide to use choose directory functionality in any GTK-based application it's really troublesome to choose directory from current path.

Example (based on Transmission GUI but it's the same in all such dialogs):

Transmission specific part:
1. Chose any downloaded torrent like ISO with latest Ubuntu or Debian;
2. From context menu chose 'Set Location…';
3. Select 'Other…' from drop-down list;

Let's assume we are in the ~\Downloads\Ubuntu\11.10\ directory right now because this folder were previously selected when different torrent were added.

Generic part:
4. Click on previous directory in the path above (buttons) on the left side from current folder (Ubuntu directory in current example).
5. Click 'Open…' button.

Expected result:
Ubuntu directory are chosen. Active directory must be chosen because user clicked on it.

Actual result:
11.10 directory are chosen. We were in 11.10 directory and... we still in 11.10 directory! On the step 4 name of the next folder in the row appeared in the 'Location:' filed (which expected to remain empty, nothing were typed by hands).
If you chose 'Download' directory it will open 'Ubuntu' directory instead. If you chose 'username' directory it will open 'Download'. >_<

I think it's really easy to fix. Just leave 'Location:' field empty/unmodified when user click on the directories in the path. Right now behavior is really confusing.