* The actual problem is that we get the "playback finished" event
before the actual track has finished playing. This is on purpose, so
we have time to load the next track. When we load the next track, we
cannot update the GUI yet, since the old track is still playing. So we
set a timer which fires whenever the new track actually starts
playing. Once the timer fires, we update the GUI. The timer is set
based on the length of the track and its current position. So if the
length information is incorrect the timer may fire too late or too
early, causing things like repeating tracks (the GUI thinks some other
track is playing).