How many UAs make it possible, let alone easy, for authors to
edit References or In-Reply-To fields?
For that matter, how many permit a user to select multiple
messages to compose a response citing all of the selected
messages (including appropriate setting of In-Reply-To and
This is probably an area where some advice to UA authors
is called for.
seems like we need some experiments before making such recommendations.
we can usually guess how a protocol will function without extensive
real-world testing. this doesn't work nearly as well for user
interfaces. humans are a lot less predictable than machines (alas :)