Why is the text messed up in that way? It has been happening severalBasically the app is messing up re-drawing after an expose event. Forcing another expose over the offending area will generally fix it. I haven't seen it in action, but I think from what you say that if the app gets an expose event at around the same time that it is scrolling or painting text, it gets confused.
times today. Never mind what it says: I noticed the problem while
working on a private file, and just pasted in something I could send
online. For the record:
Basically, it's a bug in the app and you should be able to clean the screen up reliably by running xrefresh.