Google Chrome is probably one of the stricter browsers out there in terms of highlighting SSL errors.
However once you have viewed an HTTPS page with mixed content, Google Chrome will continue showing you the mixed content warning (a red line through the 'https://') for as long as you stay browsing the same domain, even for subsequent pages which only include other HTTPS resources. Only once you navigate to another domain, or open a fresh tab does it tell you you're secure again.
What is the danger it's protecting you from here? How could mixed content on a previous page actually affect the security of subsequent secured pages? I understand that mixed content should be flagged up, but there must be a specific reason that Google is persisting this warning, other than "Well you still need to know about it"