Hi Uwe, On 21/04/2009, at 8:30 PM, Uwe Lück wrote: > I wonder whether this is a bug that should go to the LaTeX Bug > Database, since it only > -- is about an internal > -- contradicts what one might expect > -- while it is not clear to me whether this can affect LaTeX's > function on the user-level This certainly seems like a bug to me, although I had to modify your examples to see the error: \documentclass{article} \begin{document} \makeatletter \in@{bonbon}{bon}\ifin@ YES\else NO\fi % gives YES \in@{bonbon}{bonb}\ifin@ YES\else NO\fi % gives NO \in@{client-to-client}{client-to}\ifin@ YES\else NO\fi % gives NO \in@{client-to-client}{client-to-}\ifin@ YES\else NO\fi % gives YES \makeatother \end{document} The tendency seems to be not to change the internals of LaTeX2e, but I'd be happy to replace the current implementation of \in@ with a more correct version. What do others think? If others are amenable to the change, would you be willing to write the new version? Cheers, Will