Stuck waiting for proxy username/password
 

Even though my web proxy information are in the keychain, sometimes when using SP 15, a modal dialog pops up asking for that information for a random bookmarked page. The red close button is disabled, and it doesn't disappear on either Cancel or OK, whether the information is entered or not. So, SP 15 becomes unusable at work behind the firewall.

Do you use a pem file to configure your proxy by any chance?

Nope, I don't even know what a pem file is.