From m60 onwards an additional document language option of "default"
is available which is resolved at runtime from the session's locale
settings to the best fit document language for the current session.
This extends the older behaviour of detecting the best fit document
language only at first-start and disregarding the locale settings at
The new setting of "default" is the new default setting. Manual
selection of a new default document language remains unchanged and
overrides the auto-detect feature.