[NTG-context] Filler rules

[Willi Egger]

Good afternoon!

I am dealing with a book, which has a short black rule under the title of the chapters.

I see, that the old rule mechanisms are no more available in LMTX and are replaced by fillers.

Now with the following setup, I would expect a 50mm line placed centered. Hoewever this seems not to work in this way. 
What am I missing?

kind regards

Willi

\definefiller
 [Titlerule]
 [alternative=rule,
  left=\hfil,
  right=\hfil,
  method=local,
  width=50mm,
  height=2pt,
  leftmargin=1pt,
  rightmargin=1pt,
  align=middle]

\starttext

\midaligned{Some text}

\filler[Titlerule]

\stoptext