These are fairly old ones I think, but I'm mentioning them again because I just rediscovered them.
The References: header does not split onto more lines and/or be reduced in size, causing an error from the server when sending in particulary long threads "Line exceeds maximum length" (or something like that) Editing a message deletes the references header and (as I discovered) replaces the From: address with the one from the "Accounts" settings rather than keeping it the same. Chris