Playback problems with down/up arrows
AFAIK, for guitar music, the arrows (from arpeggios and glissandos) normally indicate a downward or upward strum. However MuseScore interprets them like arpeggios which creates a playback issue. You can hear this for yourself by creating, say, a measure of 1/8 note guitar chords in Em (EBEGBE) and putting strum arrows in front of them. Then listen to the sound without arrows.
I would suggest that MuseScore should ignore the arrows when playing back as this gives a much better sound.
Another issue came up when trying to use the Piano Roll editor to try to correct playback: it only allows you to edit one note at a time although you can make multiple selections by dragging! Is this a bug?