Tags cannot applied to 'Write' messages because the email needs to exist before a Tag can be applied and so when you edit that message it loses any Tags because it is seen as a new Write message saved as draft.

If you right click on draft email and choose 'Edit as new message', then the original will remain in Drafts with the Tag. When you save the edited email as draft, it will not have a Tag.

I have located a bug which was originally requested some time ago, maybe you could add some information like what OS you use and version of Thunderbird. You could also vote for the bug. you would need to register to post comments and vote.

• https://bugzilla.mozilla.org/show_bug.cgi?id=497105

Running Windows 10 & latest update Thunderbird 45

"If you right click on draft email and choose 'Edit as new message', then the original will remain in Drafts with the Tag. When you save the edited email as draft, it will not have a Tag." Sorry, that is no help. What's the point of having a redundant version of the email tagged, & the new version - the one I want - not tagged? I still don't have a tag on the one I want.

Technically, I see what you mean about writing new email but functionally, it makes no sense - I think it needs to be fixed. If an email already exists and I have identified it as being "important" or "personal", why would I not want it still to be classified that way after I've edited it?

I see your point, but you need to post info into the bug report to get them to realise this inability to retain a tag on edit/edit as new is something that needs consideration.

I'm using OSX 10.10.5 . Just updated Thunderbird to 45.2 to hopefully fix a disappearing act of message tags in my inbox (Usually use #1 and 2).

Didn't work. I tried the community suggestion of Safe Mode and removed add-ons. Still doesn't work. When I close my window and return, all marked messages no longer have a tag. I have missed important contact times because I didn't see my "alert tag."

Help?