Somehow, cleaning up useless software (using software center), I uninstalled Ubuntu "system settings". I did this by mistake. Now I fail to find system settings application using software center (and there are so many items in history...).
It seems strange to me because usually when I try to uninstall something critical (system testing for example), the dependencies manager tells me It will uninstall the whole desktop system then. I am sure I did not have that warning.
So I need the name of the software to install or a command line command rather than a system restore to get it back.
Very interesting thing. If you ever want to play with this and reproduce it, you will be confused to see Ubuntu Mobile system settings instead! Yes, mobile network and touchscreen settings! Happy pre-release viewing!