Getting gtk 3.0 themes to work in Openbox

One small glitch I discovered was the lack of GTK3 themes with a corresponding GTK2 alternative and a gtk-engine needed to coherently display the UI for several GNOME applications from the default install such GNOME Character Map, Disk Utility, Transmission. So the latter appear un-themed and rather ugly in comparison to the other GTK applications in the default selection.

I have fixed this cosmetic deficiency by installing gtk-engine-unico (that is needed by most of the GTK3 themes anyway) and a theme that has both a GTK2 and 3 variant. The GTK2 variant can be selected through lxappearance, but in order to make use of the corresponding GTK3 theme, its gtk-3.0 folder should be copied into ~/.config. Please note that lxappearance creates a ~/gtk-3.0 folder that might be a bug in lxappearance 0.5.1 dealing with GTK3 and needs further investigation. I have found that this directory is not utilized in any way and may be safely deleted to keep ~/ clean

source: http://bbs.archbang.org/viewtopic.php?pid=6895#p6895

see also: https://bbs.archlinux.org/viewtopic.php?id=119251