3

There is no way to keep python3 as default on Ubuntu 16.04, because many programs including apt are written in python2. And there is absolutely no need to set python3 as default as you can run python3 apps using python3 appname or setting python3 in shebang. You can set back default to python2 by running: sudo rm /usr/bin/python sudo ln -s /usr/bin/...


3

Is the Multiverse repository already enabled? Check in Software and Updates (the fourth line of repositories). If not, do sudo add-apt-repository multiverse && sudo apt update or enable by clicking on it then clicking [Close]. Once Multiverse is enabled, run sudo apt install flashplugin-installer then close Firefox if it was open. Relaunch Firefox ...


2

One can get an idea of the software offered by Ubuntu Mate's Software Boutique by downloading the contents of this link as sb.html and then running grep -n name sb.html The list has 5782 entries currently. gcolor2 isn't one of them. However, in gcolor2 package missing in Ubuntu 18.04?, there's an answer describing how gcolor2 can be installed in any 18....


1

Many updates, but not all. There's a lot more to Ubuntu and Linux than GNOME knows. In addition, you are almost always better off sticking with what's in the Ubuntu repositories.


1

I just got the answer this morning, when I booted with another Unifying receiver inserted. It works without any issues.


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