Use which_element_editor when Rich Text is off

Is it possible to use the element editor, specified in System Settings by the key which_element_editor, as a fallback editor when Rich Text is turned off on a resource?

As far as I know there is no way to configure this. However, it might be possible to use a plugin.

You can install the ACE Plugin http://modx.com/extras/package/ace. By default when TinyMCE enabled it will only activate in snippets and chunks etc... but you can configure this in the site configuratione

ACE is installed and is set as which_element_editor, but I can't seem locate the setting you are referring to, Chris.
I looked under both namespace:core, area:Rich-Text Editor and namespace:ace...