Description of problem: If the gnome-shell extension "User them" is no on (enabled) then only the "standard" gnome-shell theme is used (/usr/share/gnome-shell/theme/). To see and use any of the gnome-shell themes that may be installed under /usr/share/themes/ then "User themes" must be on. This does not make sense to me! Version-Release number of selected component (if applicable): Fedora 19 How reproducible: everytime Steps to Reproduce: 1. 2. 3. Actual results: Expected results: Additional info:
GNOME Shell appearance is not customizable by defaut. This feature is only available if the user-theme extension is installed AND enabled. That's why gnome-tweak-tool requires it. This extension allows users to select themes installed installed in its directory (~/.themes for GNOME 3.8) OR in /usr/share/themes. I suppose the name/description of this extension is a little bit ambiguous for you, since it doesn't mention explicitely its ability to load themes from /usr/share/themes. In such a case, you should report a bug for this extension to make it clearier.
(feel free anyway to reopen this bug if the way I understood this bug report is erroneous).