\definehead[LevelCHead][chapter]
\setuphead[LevelCHead][style={\tf\it},alternative=text,number=no,page=no]
\starttext
Hello world!
\LevelCHead{Hello world!} Donec placerat. Nullam nibh dolor, blandit sed, fermentum id, imperdiet sit amet, neque. Nam mollis ultrices justo. Sed tempor.
\stoptext
gets
! Extra \else.
\doplaceheadtext ...er #2}\makestrutofbox 0 \else
\setbox 0=\ifvertical \vbo...
\dodododoconstructhead ...{\finalsectionnumber }}}
\writesection {#1}{-}{#4}\...
l.9 \LevelCHead{Hello world!}
Donec placerat. Nullam nibh dolor, blandit sed...
?
Alan