I've executed your script, and it did run, and downloaded some things, but also generated some errors. (A lot of "MPD:connection refused")
After the reboot the problem was the same (Slow scrolling in the app and Chrome, fast scrolling with Firefox), so now I'm restoring a backup of last June.
I made a backup because I have a display and powerbutton connected, and installing it from scratch is a lot of work.
I'll come back with the results.
Do you know what browser the RuneAudio App uses? Is it also using Chrome, or something else?