I use Firefox and Thunderbird for browsing and email. In the Safari Preferences, Firefox is set to be default browser. Each time I start Firefox, it asks if I want it to be the default browser. Same thing with Thunderbird. If I disable this check in Thunderbird, and click a mailto-link on a webpage, Apple Mail opens.
How can I set Firefox and Thunderbird to be the default clients, without having to confirm this each time I restart my computer?