[paulhagstrom]

I had one other thought on this topic: I am running Windowshade X, which might be doing something to the topmost window. I'll try disabling it and see if the sporadic hiding behavior fails to reappear, but in case anyone is seeing this problem and also has WSX running, I thought I'd suggest that as a possibility.

[Update: Guy Manchester on the Quicksilver list reported that WSX was causing the same problem I'm seeing with Quicksilver, so it's quite likely the cause with OmniFocus as well.]