The wiki shows two thumbnail samples. I like the first one. But I want to use MKIV. When I do the first sample blows up on the second chapter entry. Obviously there is some code in sample 1 that doesn't work under MKIV. By a process of elimination it centers on the thumbnail description proper. The file looks like this: --------------------------------------------------- \unprotected \def\rawsectionnumber#1{\countervalue{\??se#1}}%will be in kernel \setuppagenumbering [alternative=doublesided] \setupcolors [state=start] \setupbackgrounds [page] [background=thumbs] \defineoverlay [thumbs] [\setups{thumbs}] \def\NOfChapters{4} % i need to make this one available \startsetups thumbs \definemeasure[thumbheight][\dimexpr\paperheight/\NOfChapters\relax] \vbox to \paperheight \bgroup \vskip \rawsectionnumber{section-2} \measure{thumbheight} \vskip -1 \measure{thumbheight} \doifoddpageelse\hfill\donothing \framed [background=color, backgroundcolor=darkgray, frame=off, foregroundcolor=white, height=\measure{thumbheight},width=1cm] {\bfa \rawsectionnumber{section-2}} \doifoddpageelse\donothing\hfill \vss \egroup \stopsetups \starttext \chapter{first} \dorecurse{10}{\input tufte } \chapter{second} \dorecurse{10}{\input davis } \chapter{third} \dorecurse{10}{\input zapf } \chapter{fourth} \dorecurse{10}{\input bryson } \stoptext ----------------------------------------------- It works under MKII but not under MKIV. The error message occurs after the first chapter. But the chapters by themselves work OK. I will continue to experiment---- -- John Culleton Wexford Press Free list of books for self-publishers: http://wexfordpress.net/shortlist.html PDF e-book: "Create Book Covers with Scribus" available at http://www.booklocker.com/books/4055.html