If I am in Projects or Contexts (or a Perspective) and I select a particular Project/Context from the side list, I’ll see only the tasks under that Project/Context.
How can I then unselect it so I can go back to viewing all the Projects/Contexts?
A Command+A will do it, but then it actually highlights EVERYTHING, rather than unselecting the item in the side list that I just selected?
If you click on a sidebar tab which is already active, it will reset its sidebar selection and search filters to their default state. (For Projects and Contexts, that’s empty. For a custom perspective, it’s whatever you’ve defined for that perspective.)