I'm using portable Thunderbird on my computer to keep everything in one folder.

I'm also using portable Firefox for the same reason, but there is a small app called RegisterFirefoxPortable (86k) by Ramesh Srinivasan (26/08/2008) that creates an entry in Default Programs (Mozilla Firefox, Portable Edition).

I do not want to bypass the portable app by making the original Thunderbird executable the default app (Options).

This is what I want, but for portable Thunderbird:

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