same issue here, disabled 3rd party repos in software-sources gui, then removed 3rd party sources in software-sources gui, then removed from /etc/apt/sources.list.d/ at CLI, had been refreshing software sources every time i made a change... no luck, old ppa's still showing up in Software Center... tried completely removing and purging Software Center, on reinstall, old sources are still present.
same issue here, disabled 3rd party repos in software-sources gui, then removed 3rd party sources in software-sources gui, then removed from /etc/apt/ sources. list.d/ at CLI, had been refreshing software sources every time i made a change... no luck, old ppa's still showing up in Software Center... tried completely removing and purging Software Center, on reinstall, old sources are still present.