Home, end, page up/down not working in Galley View

Sometimes the home, end, page up and page down knobs don’t work in Galley View. In Page View they work just fine.
Strange thing is that some files have this problem, others don’t. When saving the file, exit and restart Dorico, then after reloading the files, the behaviour is the same (meaning the same files have the problem, the others don’t).

Any ideas?

Can you attach one of the projects that you’re having problems with here, so we can take a look and see what might be causing the difference in behaviour?

The problem did vanish suddenly. At the moment all files are OK, exept for one with which zooming in and out seemed to help. It might just be a little bit of instability here and there. I’ve had it before…
I don’t think attaching one of the files is very useful, so thanks anyway.