The first thing I noticed after upgrading from 11.04 to 11.10 is that my wallpaper changed to the one I used to have ages ago - probably before I upgraded from 10.10 to 11.04. Which is not a big deal, of course, but:
My daughter used to experiment with Gnome themes in her account on the same machine - you know, bright-blue window backgrounds with yellow text etc. Later she changed the settings to something more usable. After the upgrade to Oneiric, the Gnome theme reverted to blue backgrounds with yellow text and I can find no way to reset it.
I installed the "Advanced settings" tool and can change the theme there, but it looks like most of the themes fall back to some default settings for window and text colors - i.e. window decorations and other elements change, but the blue and yellow "shine through" the theme. Previously it was possible to edit the defaults but with the "streamlined" Gnome 3 UI I can't find where it is done.
The only theme which override the blue background is High Contrast theme - but it's just too ugly to be used.
Can somebody explain what caused this "time machine" effect - the settings in question were last used many months ago and then changed via standard Gnome means.
How do I remove the theme customisations and roll back to the stock standard theme?