Excellent Add On Rated 5 out of 5 stars
It is utterly ridiculous that there is not a default Next and Previous button built into Thunderbird!! I am so glad that you created this add-on and I have been using it for years.
I was extremely disappointed when I upgraded to Thunderbird 5.0 and it wasn't compatible. Luckily though, I decided to give the usual editing of the install.rdf file a try (instruction here: http://kb.mozillazine.org/Editing_an_add-on_to_change_its_compatibility ). I changed it to indicate "<em:maxVersion>5.0</em:maxVersion>" instead of "<em:maxVersion>3.2a1pre</em:maxVersion>" and the it WORKED!!!! (for the most part). After dragging my Next and Prev icons into my toolbar, they became blank. But they are THERE...and they WORK! So if anyone else using Thunderbird 5 wants this add-on, it will work, with a little finagling. It should any easy upgrade to make it officially work in 5 though. Thanks again!!