Remove Smart Groups / Rules does not work

Trying to remove some of those I created myself but no longer need, either by hitting backspace or right-click remove. Nothing happens. Quitting DNT 3.5.2 didn’t change that. What am I dong wrong?

Removing a smart rule moves it to the trash here.

Does the sidebar actually support keyboard navigation, see Preferences > General?

I can’t see this option in Preferences > General.

not with me …

See Preferences > General > General > Sidebar

Sorry, I was blind. Yes, that checkbox is checked.

Just tried this successfully. Which version of macOS do you use?

10.15.6

Are you able to remove them via the contextual menu?

No. It gives an “acoustic feedback” that it does not work.

And after rebooting the computer?

… that did it …