Thanks Jon, I will see if that works better for me. I think I've seen you mention that before, but haven't used it. Having the responses to killed comments invisible should be a boon. A killer feature, if you will.
I'm familiar with other forums where I have to poll, but can then see unread messages. What it does mean is I have to stop bothering with the RSS feed - and remember to poll for unread comments. I'll keep a feed to LWN news though.