How to DEselect a range?

I have a curious problem. I’ve divided my track list into 2 part, per the Cubase function that does this… you know, so you can keep certain tracks always visible up top. OK, so, I accidentally selected a range inside that top part. Well, if I click somewhere else up there that’s outside that range, the range goes away, but a little blue line is created as the beginning of the next range. So, technically, I’m not deselecting anything. Well, aha… I figured I can choose the “select none” command, Shift+Ctrl (Cmd) + A… and that seems to work.

But here’s the kicker, and why I care about deselecting… if I now select a range in the lower track list, and then try to zoom in on that range, it acts as if I also have something selected in the upper track list and zooms into that as well… I mean, it includes that upper part in the zoomed in area such that I’m not actually fully zoomed in on the thing I want to be zoomed in on in the lower track list.

Gosh, I hope that makes sense.
What gives?
Am I deselecting correctly?
Is this a bug?
How would you fix? I guess I could un-divide the track list and then divide it again, see what happens.

Cubase 12 Pro, Mac OS Big Sur.