the new "mouse over" "stats" pop-up will pop under an embedded video
Find a comment with an embedded video attached.
mouse over the commenter's name
watch the pop-up be obscured by the video.
(Ubuntu w/ Firefox 3.0.19)
I saw this a few weeks ago, but have not retested since then because embedded vids in comments are rare. If I see it again, I'll try for a screen shot unless it's a known issue by the staff.