This is Composer 2013 SP2 Build 126.96.36.1994 (2/13/2013)
While I was working on my composer document I had a hard, nasty crash-had to reboot my machine to get the composer window to display correctly-and have since noticed a little balloon-black text, white background-that says "Id"
It's about 40% of the way up from the bottom and appears to be set to a Free2D location which puts it in the middle of every one of my views.
Some fun facts:
the annotation is not selectable.
the SMG file has no entities in the Annotations or Callouts branches of the Collaboration tree. It's there if I had all of the actors. It's there if I hide all of the collaborators
If I go into the BOM work shop and click "Delete Visible Callouts" or "Show/Hid Callouts" there is no effect on the annotation.
The balloon appears in images created by the hi-resolution workshop, but not all of them.
-and after crashing while trying to write this, I can't reproduce the problem.
If you've seen this before let me know.