-open up chromium
-go to google music (google.com/music)
-start playing a song
-the chromium pop-up will show displaying the artist and track name (i think default is for it to pop-up in the bottom right)
-you'll see a small opaque white box show in the top left
as stated previously, restarting compiz makes the white box go away
this isn't 100% reproducible, but pretty close:
-open up chromium
-go to google music (google.com/music)
-start playing a song
-the chromium pop-up will show displaying the artist and track name (i think default is for it to pop-up in the bottom right)
-you'll see a small opaque white box show in the top left
as stated previously, restarting compiz makes the white box go away