If I select multiple dungeons, the list sometimes grows very long, I'd like an option to remove (i.e. ctrl+click) items to remove them from the list if it's something I'm not interested in.

Looks like a duplicate of #96

I propose toggle hiding with ctrl+click and a checkbox "show hidden".

Doesn't look like the maintainer currently has time to review pull requests.
@DomenikIrrgang I would work on this if you accept the idea

If you can please try the version here https://github.com/terrorfisch/ClassicLFG/tree/feature/hide_groups and report any problems :)

That would be awesome.