Using the RichText editor in Safari 4.0.3 I pasted some text over existing text in Confluence, then choose to undo the operation, and re-did it again. The behaviour is buggy so I tried it a second time. It still did the same thing the second time, but also crashed my browser. Unfortunately it didn't seem to save the Draft and I lost 30 minutes of work. The earliest draft in my list is from more then 40 days ago.

I should also mention that I used the full screen mode for editing.