"Create Slash Region" only replaces notes on upper staff

[soundsgood]

I imported a MIDI piano part, which I’m replacing with chord symbols and slash notation. Each time I select an entire bar of notes, then choose “Create Slash Region,” Dorico 4 replaces only the upper staff with slashes, leaving the lower staff full of notes. I then have to reselect the notes on the lower staff and hit delete.

Is there a way to make “Create Slash Region” delete all selected notes, so I don’t have to reselect and delete the notes on the lower staff?

Here’s what I’m selecting:

And here’s what happens after “Create Slash Region”:

[Lillie_Harris]

I think you need to input slash regions on each staff separately, but once you’ve input one, you can duplicate it to the staff below.