It works on Fennec 16 XUL for Maemo 5. Rated 4 out of 5 stars

But it generates a lot of css-related warnings in Error Console.

Rated 5 out of 5 stars

I have liked your idea, and I would like to make a modification of it (for resistive screens, any textbox, Morse-code based, with possibility to modify Morse code for yourself).
But first, tapsure doesn't work for me (at all).
Maemo 5, Fennec GTK nightly 2011-01-19.
TAPSURE.strings is null
overlay.js
line 244
Chrome registration is without problems, I can see overlay.js, overlay.xul and the locale files, so I cannot pin down the problem immediately.

This review is for a previous version of the add-on (1.0). 

That's very strange; I don't see why that would be failing. If you email me at cfinke@gmail.com, I can send you a copy of Tapsure with some modifications to try and fix the issue.