Occasionally after I type half an email message, Opera will decide paragraphs just don't make sense. It'll either start adding line breaks instead of word wrapping, or just let one line become very long, to the point where you would have to scroll to read it. There's no discernible pattern, nothing I do to trigger the browser's acid trip mode. It'll either work or not work on the same page depending on the day. Anybody else run into this kind of trouble?
I've been using FireFox for a few years, but it's been seizing up on me lately. Other than the text area madness, Opera is pretty sweet - half the memory usage, a little faster, better threading. No FireBug, but ... I'd switch from FF if I could write emails and get normal paragraphs.
I frequently switch between the two or IE,usually opera the most. I haven't noticed any probs bu then i use outlook or hotmail or yahoo for email.
I use gmail, which is notoriously ajax heavy, so that may have something to do with it. I've been having a lot more trouble in WordPress lately, but that uses a great deal of jscript, too, although I don't think much of it is async? There's probably some type of scripting in the editors it doesn't like, then?
I use Opera and I have noticed the Gmail text area issue at times. This has been hapening less but the intermittent behaviour suggests something at the Gmail side and not Opera. As for other text area inputs, I have had no issues. I regularly edit blog/website/cms etc using Opera. In the case of the Gmail, are you using th http://mail.google.com/mail/?ui=1&disablechatbrowsercheck=1 link?