Hi, Wolfgang.

I tried dropping in the Lua code, but it does not extract the text:

\define[1]\StyleChapter{%
\StyleChapterFramed{%
    \framed[align=right, frame=off]{%
      \startoverlay
        \color[ColourSecondaryLightest]{%
          \cldcontext{string.sub(#1,0,1)}
        }
        \vskip-1.9em\hskip1.2em#1
      \stopoverlay
    }
}
}

! LuaTeX error [string "\directlua "]:1: bad argument #1 to 'sub' (string expected, got nil)

I've tried a few variations:

          \directlua{string.sub(tex.sprint("\luatexluaescapestring{#1}") }
          \directlua{string.sub("\luatexluaescapestring{#1}",0,1)}
          \directlua{string.sub(tex.sprint("#1"),0,1)}
          \cldcontext{string.sub(tex.sprint("#1"),0,1)}

Any ideas?