Rated 5 out of 5 stars

I have a hack to make this with with TB3, unzip the xpi, then unzip identityreminder.jar in the chrome dir, then in the content directory, apply the following patch below to identityreminder.js.
In the top level, apply the patch below to install.rdf.
zip it back up and install.

************ Install.rdf patch **********************
24c24
< 1.5.0.*
---
> 3.0

*********** Identityreminder.js patch *********************
65c65
< msgComposeService.OpenComposeWindow(null, null,
---
> msgComposeService.OpenComposeWindow(null, null, null,