Rated 4 out of 5 stars

I have been looking for an add-on that will do this and am very glad to have it. However, the editing window needs to be three or four times as long before it will be really useful to me; I need to be able to see the whole subject line to make editing easy. I tried to drag the edge of the dialog box to achieve this, but it was a set size.

Léirmheas ar leagan níos sine den bhreiseán seo (1.0). 

New Version 1.0.1 waiting for review: https://addons.mozilla.org/fr/thunderbird/addon/edit-email-subject/versions/

With wider and resizable edit window

Rated 4 out of 5 stars

It would be nice if this tool could make changes persistent by changing the real header of the email (at least optionally)!

Otherwise, on a shared IMAP folder it doesn't really work sorting emails when the new correct names are not available to all users :-(

Léirmheas ar leagan níos sine den bhreiseán seo (1.0).