Probably not an issue with the site, but until a day or so ago I never encountered this problem, so I keep an open mind. Using Firefox 47.0.1 (the most recent for my preferred platform), with user agent set to Firefox for Windows. Various extensions. Symptom: when I reply to a topic, there's the progress indicator at top right – endless – so it appears as if the reply is not posted but if I (Control-R) reload the page, I find that the post succeeded. Any suggestions? Has anyone else found those symptoms and if so, are they associated with a particular extension (or combination of extensions)? The problem does not occur when I begin a topic.