Mixed content blocking was FireFox's answer back in version 23. Since version 55, Firefox allows mixed secure content so as not to break a web page and is the reason for the following security alert in the address window of Firefox browsers when viewing pages of this forum. (black padlock with superimposed yellow triangle)
When a user visits a page served over HTTPS, their connection with the web server is encrypted with TLS and is therefore safeguarded from most sniffers and man-in-the-middle attacks. An HTTPS page that includes content fetched using cleartext HTTP is called a mixed content page. Pages like this are only partially encrypted, leaving the unencrypted content accessible to sniffers and man-in-the-middle attackers. That leaves the pages unsafe.
Probably because Chrome is written to ignore this mixed secure content event. Netscape shows you the warning.I see no flags of insecurity with updated Chrome on Win7x64.
... a grey lock means that the website is encrypted and verified, a green lock means that Microsoft Edge considers the website more likely to be authentic. That’s because it’s using an Extended Validation (EV) certificate, which requires a more rigorous identity verification process.