EDIT: Not something I've noticed before. Has it always been like that? Looks like the account / store pages are secure anyway. Obviously I've put in or stored no details there anyway :)

Looks like it's happening on some pages and not others. Close the store until fixed? At least keep a very close eye on it!

"A gray padlock with a yellow warning triangle indicates that the connection between Firefox and the website is only partially encrypted and doesn't prevent eavesdropping.

For information about what "partially encrypted" means, see Mixed content blocking in Firefox. This is a problem the site developer needs to resolve.

Note: Do not send any sort of sensitive information (bank information, credit card data, Social Security Numbers, etc.) to sites where the Site Identity button has a yellow warning triangle icon. "