On Tue, 2022-03-08 at 13:40 +0000, Patrick O'Callaghan wrote:
Although I haven't looked closely at this, I think the same is going to happen with any desktop MUA, given that Gmail implements this via its own non-standard "magic". If they used IMAP labels it could perhaps be made to work, but I don't think they do.
I've had a play with labels in Evolution. The first label you make becomes label 1, the next one label 2, and how your client colours them is up to it. It doesn't matter what purpose you give them. If you, then, read the mail in another client, they may not be considered the same labels. Certainly not if you'd already made some labels in it.