Bugzilla

This bug prevented me of using Thunderbird 10 years ago. I gave another try some days ago, using obviously a different computer and a different OS, and the exact same bug is still here. The ability to UNDO is one of the most useful features of any software. Its a shame that a such persistent bug like this will keep preventing me of using one of the otherwise best email clients.

Look, theres another one, this one 13 years old: bug 467841
And yet another one, this 16 years old: bug 323875
And theres one opened by me 2 days ago: bug 1752569

And Im sure there are a ton more threads reporting this same bug.

Why do all email clients support UNDO and Thunderbird has had trouble with it for the last 16 years (at least)? Its time to solve this once and for all, don't you think? 16 years and you still have problems with this?

I see people here discussing if IMAP gmail implementation supports it or not, and stuff like this. Again I ask, why does it work with all email clients and not with Thunderbird? 
Its not a problem of IMAP, gmail, ot whatever. Its a problem of Thunderbird. Stop complicating stuff. Its a simple move back operation.

And I will ask a final time: Why does it work with all email clients and not with Thunderbird?