It is currently impossible to switch from one directory
to another without going up and down in the directory
view over and over again.
Imagine you would like to compare icons in
/usr/share/pixmaps and /opt/gnome/share/pixmaps. Or
maybe even /opt/gnome/share/icons/Clearlooks/16x16/gtk
and /opt/gnome/share/icons/Clearlooks/24x24/gtk. It's
Opening another window for that is not a solution,
imagine you would have to compare three or even five
icon themes, it clutters the taskbar with countless
windows! You have to bring another window to the focus
and then send it to the background over and over again,
but it could be so easy with a tree view.
This is a major usability bug, although tree views have
been deprecated by GNOME usability experts. gthumb is
hardly usable in the current state for people who
compare icon themes. To be honest, I would really like
to use an open-source image viewer without KDE
depencencies, but currently there are none with a tree
view, so I must use XnView.