Until recently, it used to be true that no matter which personality an event invitation received by a Thunderbird user was sent to, the Accept/Decline response was sent from "main" personality. (How was this determined? First entered during setup? Top of the list? I don't know. Doesn't matter.) This was both an operational and a privacy issue, since it's often not appropriate to reveal, for example, a personal email address to a business contact, and will often be confusing to the recipient of the response. In a recent update to Thunderbird, this behavior was changed such that when responding to an *original* invitation addressed to other than the main personality, Thunderbird presents a pop-up window that says "you're not invited..." and a drop-down list so you can choose which personality to respond from. Big step in the right direction. However, if there's a subsequent email received with a *change* to an event time, etc., the Accept/Decline response is again only sent from the main personality. There's no obvious way to change this. This needs to be fixed. A possible fix would be the pop-up window and drop-down list presented to the original invitation. From my point of view a better fix would be to send *all* invitation responses - original and change - from the personality they're received in, pretty much just like the "reply" function. Much cleaner, fewer clicks, right outcome. Perhaps there's a reason not to take my approach, but I can't think of it. At a minimum, my "possible fix" should be implemented.