[luatex] The use of \delimeterfactor and \delimitershortfall with math accents

[Khaled Hosny]

Hi all,

While trying to implement support for extensible math accents in XeTeX,
I noticed that LuaTeX takes into account \delimeterfactor and
\delimitershortfall while computing the desired size of the accents
(mlist.w l.2195-2197), but this does not follow the MS Office
implementation nor TeX behaviour (not even plain TeX's faked accent
implantation of \overbrace), so I'm wondering why it is done that way
and wither it worth breaking compatibility with MS implementation or
not.

Regards,
 Khaled