How do I change the mailto: Mail Handler in Firefox?

Setting Firefox's mail client

1. Click the menu button and choose Options.

2. Select the Applications panel.
3. Search for the Content-type: mailto and select it.
4. Click on the Actions column in the mailto row, to change the action. 

**Please be aware that once this is corrected they will need to right-click on the (Email Class) link and choose to open in new tab**