I had/have this problem. For me, fix was simply running WordPress in window instead of full screen, so a scroll bar to the right shows up instead of getting buried off the screen to the right. Just poor coding, could be called a bug I guess. Very frustrating at first, but the fix is easy.
I’m the person who Diane did the upgrade for, and it’s working well other than this one glitch. Prior to the upgrade my comment notification emails arrived with the commenter’s return address in the “from” field in Outlook. Now they don’t. I doubt my server host changed this at the exact same time as the upgrade… So the question is still, what’s different about 2.09 that would cause this? It’s a drag. I send a lot of private email replys to my commenters.