Padlock doesn't disappear for me, perhaps you just have a misconfiguration. Maybe a browser plugin interfering with something? Have you tried using a different browser to see if you still had the problem?
It happens on several browsers. Here is an image.
snip
I should add I live in a country where government surveillance is famously intrusive and the government makes no effort to hide the fact that it monitors my electronic communications. The internet connection I use is not secure at all.
are you sure you are not infected in some way? you should do a scan with multiple antivirus/anti-rootkit/anti-malware
usually there are insecure link, when this appear, you could have some insecure connection going on
