Scroll using keyboard arrows?
2.0.3 on Win7/10
You can scroll up and down through documents in other programs using up/down arrows, so why not in MuseScore? Left/right arrows could also be used to navigate through scores in "Horizontal scroll" mode.
It goes without saying that keyboard arrow navigation would only be possible when there was NO element selected on the score page.
Comments
The up/down arrows already serve a diferent and very important function - changing pitch of notes. I don't think it's a good idea to radically change the behavior of the keys depending on whether anything happens to be selected. Instead, simply use Page Up/Down. Note up/down normally serve to scroll only in programs that don't have a cursor - eg, not in text editors or similar programs. So just as in MuseScore, you need to use Page Up/Down there too.