Reported on forum by OleJ, confirmed by ronilse
Tested with MP 0.2.0.0 + svn--09-20-2006--01-27-Rev10374 & skin BlueTwo

If you use the BASS player & have selected no visualization & when playing a track without image art, a black flickering box appear in the upper left corner & the preview screen pulsates.

h4. Steps to Reproduce
MP Setup -> Music & disable all option for visualization.
Start MP -> My Music & play a song without album art. In upper left corner a black box appear pulsating, the same is in preview frame.

h4. Additional Information
Could have came with BASS introduction since if you use DirectShow player this doesn't happen.
Thread on forum:
http://forum.team-mediaportal.com/showthread.php?t=10979