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.