Am I being hacked?
Firefox is displaying this warning to me:

This site does not supply identity information.
Connection with this site is not totally safe because it contains unencrypted elements (such as images).
Permissions: open popup windows: allow.
Clicking on "more info", on the "security" tab it says

- Site:
mail.google.com- Owner: This site does not supply ownership information
- Homologated by: unspecified
Clicking "show certificate" says there is a certificate, issued by "Google Internet Authority G2" on 04-06-2014 and valid until 01-09-2014.