Comment on WordPress CloudFlare Flexible SSL – Making It Work by Pierre.
Thank you very much for this lovely plugin!
I’ve carefully followed your instructions, and everything worked like a charm. For people having the Mixed Content alert, try first to activate the “Automatic HTTPS Rewrites” in the Crypto menu of CloudFlare. If this still doesn’t work, install the “SSL Insecure Content Fixer” WordPress plugin, activate it and configure it as indicated in the instructions. The Mixed Content problem should disappear, and you should get a green padlock everywhere.