Well, although it was happening repeatedly in the session I was in, I can't get that exact problem to repeat. However, I have had the same symptom several times from a different action - resizing the pane. This isn't consistent but I've had it in several MM sessions (not yet in 1453 - you're too fast for me to keep up!). I eventually managed to get a Jing video yesterday, but it hung while 'finalising' (just my luck!), although it seems to be there now I've killed that process. Unfortunately it's not until the very end of a 5 minute video - hope you can skip
http://www.screencast.com/t/l2e8PmtRz. Here's a debug log:
http://dl.dropbox.com/u/39561993/ArtListLimited.LOG again, apologies for its length. And here are some screen shots I took another time it happened:


Can you see that the scroll bar looks a little bigger in the first (error), but both say 228 files. The first is only showing 171 files.