It would be handy to be able to build up complex searches simply combining searches item in the sidebar.
What I mean is something on the line of:
- with a search selected in the sidebar ⌘-Clicking another search creates in the search bar a logical AND of the two searches
- with a search selected in the sidebar ⌥-Clicking another search creates in the search bar a logical OR of the two searches
Of course you can ⌘ or ⌥ click more than 2 searches and the described behaviour could apply to sidebar tag items as well.
In case of more complex searches you still have to adjust the parenthesis but I think this feature would be useful anyway.