in panels_ui you can set the width of the playlist to something like $eval(%_width%+15) , what would hide the scrollbar
the only problem is tho as soon as you have a shorter playlist that wouldn't need the scrollbar to begin with, it'd cut of more of the playist, probably the track time, which most of the time is to the right of the track name
but maybe you could get around this by automatically sizing the playlist to the number of tracks (rows) of the playlist....dunno if that's possible tho