When clicking on a theme in the tree view, the dialog freezes and the theme is never updated. After some debugging, I found that cb_theme_tree_selection_changed is called an infinite number of times when clicking an item.
I noticed the same bug! My system: Acer Travelmate 4530, AMD Athlon 64 dual-core Debian/Sid, linux-image-2.6.30-1-amd64 xfce4 v.4.6.1 (Debian)/ v.2.7 git libgtk2.0-0 v.2.17.10-1 (Debian/experimental) I get the same dialog freezing but the theme is changed after restarting xfce. When the dialog is frozen, I looked at the xfce4-taskmanager and noticed that xfce4-appearance-settings uses 30MB of memory and 50% of CPU. I also get the same bug when using the git version 4.7 of xfce4.
Bug appears since the xfconf cache changes.
Fixed in master.
(In reply to comment #3) > Fixed in master. Thanks!