I used a gmail notifier application for a short period in time and it immediately took over my browser's mailto links. Everytime I would click on a mailto: link (which composes an email from a website) it would take me into gmail. I did not want this and wanted to use Thunderbird.
After doing some searching I found lots of links on how to set your gmail as your default email program but nothing to change it back to Thunderbird. So here it is.
1. Type about:config in the address bar.
2. Type network.protocol-handler.external.mailto and change the value to true by double clicking on it.
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