Currently you need to add Data Selection rules on a source table by right clicking on the table and selecting "Add Data Selection Rule".
It would be handy to have this option in the right click menu of the field so that you can add a rule directly there. Ie if you click on the field and select Add Data Selection Rule, the same right pane opens but immediately focused on the that field.
Would again save a few clicks!
Same with add incremental selection rule when applicable.