Still, not the best or most intuitive behavior, I think. To select a note, user always clicks on the notehead, not the staff. At least this is how I think it should work.
I’m not in front of Dorico at the moment, but I believe you can set the mouse to load an item and just use a regular click if you need to input an item several times in a row. It should be listed under Preferences, General if I recall.
I believe an alternate way to achieve what you’re looking for is to just use the down arrow and invoke the key command.
I also remember reading on the forum that once you copy an articulation to one note, you can then select any number of additional notes and paste all of those in at one time, which could be a pretty big timesaver.