[NTG-context] Expansion in bookmarks

Dear all! I want to define a command that is to be used in a section title. Also I want to use \autoinsertnextspace with this command. In the following MWE, why do \This and \AName not work, while \TEX does work? I appreciate any feedback, Christoph MWE: \setupinteraction[state=start] \setupinteractionscreen[option=bookmark] \placebookmarks[section][section] \def\What{This\autoinsertnextspace} \definesorting[Name] \setupsorting[Name][next=\autoinsertnextspace] \Name[AName]{Knuth} \usemodule[abr-01] \setupsorting[logo][next=\autoinsertnextspace] \starttext \startsection[title={\What is puzzling}]\stopsection \startsection[title={\AName is puzzling}]\stopsection \startsection[title={\TEX is puzzling}]\stopsection \stoptext