I've noticed this happen for content loading quite a few web sites, not just the one you mentioned. It's not always the same request that seems stuck either.

I used the Firebug Add-on's Net tab to inspect requests and responses made during page loads - and I frequently observed that the request that appears to be stuck has actually completed already. It usually the case that another request has stalled and left the status bar out of date. That pretty much tells me that Firefox isn't reporting the actual culprit correctly.

This usually doesn't present a problem for me. Are you actually able to post your comments and see responses?

If not, I'd recommend trying the steps provided in the recommended answer listed in "incomplete loading of websites" at https://support.mozilla.com/en-US/questions/751214.

Also, if you've modified your Privacy Settings (Preferences > Privacy tab) to be extra restrictive or installed add-ons to block ads and pop-ups, these modifications may cause functionality on some websites not to work if they rely on these capabilities to perform their tasks. Temporarily disabling add-ons or restoring the defaults would be a good test to see if this the case.

Anyway - post back if this doesn't help.

Thanks for the advice. I think you're right that firefox is not reporting accurately. The web page does load completely and I am able to post comments and receive responses. I will mess around with the link you gave and see if I can isolate anything. In meantime, it's just a minor annoyance.