On the first dialog of Disk Usage theres "browse" button opening standard "Open" dialog but it seem to be impossible to select any directory using that dialog. This is confirmed copy of bug from SF bugtracker: https://sourceforge.net/tracker/?func=detail&aid=2982248&group_id=6488&atid=106488 Reproducible: Always
*** This bug has been marked as a duplicate of bug 217711 ***