<…> still see some wired behaviour on that tab (it's impossible to unfiltered a column, once you select a sorting criteria).
I really don’t have much control over the sorting capabilities. I’ve played around with the sorting capabilities on the tab for a while, and I’m not sure exactly what you are encountering. If you’d like to provide a user case, so that I replicate the behaviour, I’ll get a better grasp of the issue.
It's something I never realised, but it's spread all over the dashboard, not only in this particular tab.
How can I revert the "Keep Only" choice, when highlighting a particular value to go back to the whole list?

It's something I am sure I have done in the past, but I now cannot do that. Maybe it's the recent Tableau upgrade?