Hi,
Just started using portable versions of Firefox and Thunderbird and wondered why a different version of Firefox seems to open when I click on a link in an email. The version number is still the same, 22, but what opens does not have any of the add-on's etc. that I have installed.
If you set Firefox Portable as your default browser, you're actually setting the regular copy of Firefox within Firefox Portable as your default browser. When run, it'll run in local mode. You need to manually set FirefoxPortable.exe to open links from Thunderbird. Todo this, do the following:
network.protocol-handler.warn-external.http
network.protocol-handler.warn-external.https
network.protocol-handler.warn-external.ftp
... and set them all to true by double-clicking on them
Sometimes, the impossible can become possible, if you're awesome!