Oh gosh! I'm sorry no one has answered this yet. I saw it yesterday (or day before) but I can't really answer.
I only have a couple of ideas about this. One is maybe you got the wrong version from the repo? The other one, is that it might have something to do with your....oh rats, I'm going to have to know this, if I'm switching to Linux pretty soon. In Windows, it's called a theme. From other messages I've read, there seems to be some kind of setting within your theme, but I couldn't tell you what it's called or how to find it.
My best guess is that maybe you got the wrong version from the repo.
But hopefully a Linux user will come around, before much longer.
Or you maybe you could download from the Inkscape website? Start here:
https://inkscape.org/en/release/