There used to be a setting in Plank settings to hide the unpinned apps, super useful. I cannot find it any more. Has it been moved in Juno, or removed? Thanks a lot!
The reason why I'd hide some apps is to have things like widgets stay on the desktop, without appearing in the Plank. In the attached screenshot, see the bottom right end of the Plank: three extra icons from the widgets that I use at the moment.