Some time ago, the Firefox developers decided it was a good idea to trim the http(s):// from the address in the address bar. Since then, I’ve been getting HTTPS site where I don’t want it, because I can’t see what I’m doing. Especially so because HTTPS has no concept of virtual host names, and putting https:// in front of any domain might put you on a completely different web site. So, when I accidentally typed https:// in front of an URL once, it will remember that, but not show me…
Luckily it can be disabled, by setting browser.urlbar.trimURLs to false in about:config.
This annoying feature is right up there with the removal of the RSS icon from the address bar.
They must have followed the path that is so brightly illuminated by the one and only Google Chrome. But I feel that it’s time that they redesign their preferences dialog.