Chrome Version: 71.0.3556.0
OS: 11042.0.0

As per standard Vietnamese VNI, the users should be able to type in either way for dual-diacritic letter: tone-mark then modifier diacritic, or vice versa i.e. modifier diacritic then tone-mark.

Current "Vietnamese keyboard (VNI)" only allows modifier diacritic then tone mark, not the other way around. This is incomplete and inconsistent, because the behaviour is expected in strict mode (diacritic trigger immediately after the target letter; no need flexible diacritic trigger mode).

E.g. (non-exhaustive):

type "tra26n"
--> expect "trà" -> "trầ" -> finally "trần"
--> actual "trà" -> "trà6" -> finally "trà6n"