I have for a long time been trying to maintain a consistent look for my gnome themes especially when i apply themes of my own preference.
The problem has always been running administrative tasks, the theme then changes into this ugly default theme which i absolutely hate.
The workaround… simple, assuming you dragged and dropped a theme from gnomelook.org or art.gnome.org, it decompresses the theme to a folder in your home folder called .theme so that the path looks like $HOME/.theme/yournicetheme. To get your GUIs to maintain that consistent look, you will need to copy that theme to /usr/share/themes and that’s it.
Would it not be better to place a symlink to $HOME/.theme/yournicetheme to /usr/share/themes, which would mean that if you change it, then any changes will automatically be reflected in the admin theme?
that’s i think is a better idea we could go as far as symlinking your whole “.theme” folder to usr/share/themes