If you’re using a window manager, such as awesome or goomwwm, instead of a desktop environment, such as GNOME or XFCE, then you might have the issue of some GTK applications not looking quite right, a problem I had was with missing icons.
Before and after:
List all available icons themes:
ls ~/.icons/ /usr/share/icons/
You need to append the line,
gtk-icon-theme-name = "-insert-theme-name-", to
echo "gtk-icon-theme-name = \"Humanity\"" >> /etc/gtk-2.0/gtkrc
The above command globally sets the theme to Humanity. The command is appended if the file exists, and creates it if not.
13 Nov 2014