Change long-standing behavior reported by Deuce as an "architecture bug":

If the user does not meet the configured "Access Requirements" of the external
text/message editor that they have selected in their "default configuration",
rather than changing their default setting to the internal message editor (a
change that would become persistent as soon as the user's record was saved
in the user database), use the internal editor rather than the configured
external editor and don't change their configuration. This fixes the "problem"
of a user having selected an editor which has "ANSI" as an access requirement,
that user then logging on without ANSI support (e.g. not auto-detected) and
then logging-off which would then revert their configured editor to the dreaded
internal line editor, leaving the user to figure out how to re-select the
external (e.g. full-screen) editor they had previous configured.