@snow @design_RG this is implemented on the client side rather than the server side. I think that's okay given the short term use of mastodon - you're not likely to reply to a weeks-old post, so the interval between starting to compose a reply and sending it will rarely be long enough for you to have lost access to the original client. Attached pics are Tusky - if your client doesn't implement something equivalent, you probably want to send your feature requests to its maintainer instead.