Could you please provide the full path to the settings.ini file you created?
Originally Posted by sudo san
The applications you're having problems with, Synaptic & Software Center, are the ones that need "administrative privileges". See what you have in /etc/gtk-3.0/settings.ini.
Mine looks like this:
Where MyGreybird is what has to be entered because my gtk theme is ~/.themes/MyGreybird and NoInherits is my icon theme in ~/.icons/NoInherits.
gtk-theme-name = MyGreybird
gtk-icon-theme-name = NoInherits
gtk-fallback-icon-theme = gnome
For reasons I don't fully understand, the full paths shouldn't be used. So, you'd replace MyGreybird and NoInherits with whatever your gtk and icon themes are called. Maybe a log out and log in will be needed to get the changes to take effect.