Normally, when you click an email link and send it to your preferred email site, Firefox is only providing the details coded into the link: * "to" address * optionally, "cc" and "bcc" addresses * optionally, "subject" and "body" content The From address is supplied by your email client/website. If you need to reset the program/site that handles mailto links, please see the steps in the following article: [[Change the program used to open email links]].