After upgrading from WPHTTPS 2.x to 3.0.3, I noticed new mixed content warnings. I've read your FAQ, but I have figured out that this is caused by some new (bad) behavior in this version:
Your plugin now seems to be stripping HTTPS from URLs that are coded (on purpose) to be HTTPS. I think I can overcome this by use of a custom force-ssl hook (as documented in your FAQ), but I'd really like you to reconsider actively removing HTTPS when it's coded that way.
var pkBaseURL = (("https:" == document.location.protocol) ? "https://example.com/piwik/" : "http://example.com/piwik/");
https:// turns into
http:// under the new WPHTTPS plugin. Thanks for looking into this and any advice you can give. This is a very useful plugin overall!