BW> In themes/default/theme.ini, the default theme has:
 BW> 
 BW>         Def_Prompt = true
 BW>         Def_Text = true
 BW>         Def_Menu = true
 BW>         Def_Script = true
 BW> 
 BW> Shouldn't these all be false, as this is the default theme itself, not
 BW> some custom theme, so there is nothing (else) to fall back to?

Yes probably.  Mystic does check when trying to fall back to make sure its not already the default theme so it shouldn't hurt anything.

I'll update that in the default installation.

... Don't sweat the petty things and don't pet the sweaty things

--- Mystic BBS v1.12 A48 2022/04/26 (Windows/64)