>> So from the point of view of the UI, it looks like after TAB inserted
>> `\` we ended up in a new completion field, rather than continuing the
>> previous completion.
> Agreed. And this is a change of behavior in Emacs, it used to be
> different.
I can't remember a specific change in this area, but that's doesn't
really surprise me because the behavior of
`LaTeX--arguments-completion-at-point` is rather odd/cornercase in this
regard, so if it worked the way you liked in the past you were
just lucky.
To make sure you get the behavior you want, make sure
`LaTeX--arguments-completion-at-point` returns the same completion table
with the same start position for
\setlength{}
as for
\setlength{\ba}
It will also provide better completion, because AFAICT currently it
includes `backmatter` in the candidates for `ba`, which is not helpful.
Stefan
