Try it without the columns environment in your document, i.e.

\startchapter[title=\mytitle{Register}]
\placeregister[index]
\stopchapter


Hans van der Meer schrieb am 26.08.18 um 17:48:
Could the following setup I used be the culprit?

\setupregister[index][pagestyle=slanted,textstyle=small,alternative=A]


On 26 Aug 2018, at 17:43, Wolfgang Schuster <wolfgang.schuster.lists@gmail.com> wrote:

The real question is why do you get an index without two columns.

\starttext

\dorecurse{26}{\convertnumber{a}{#1}\expanded{\index{\convertnumber{a}{#1}}}}

\placeregister[index]%[n=3]

\stoptext



Hans van der Meer schrieb am 26.08.18 um 17:37:
How do I produce an index with more than one column?

This produces one column only:
\startchapter[title=\mytitle{Register}]
\startcolumns[n=2]
\placeregister[index]
\stopcolumns

Nor did \placeregister[index][n=2] or \placeindex[n=2], with or without the columns envirenment, produce the result wanted.
The \startsimplecolumns[n=2] environment did produce two columns, but then played havoc with the textheight.

dr. Hans van der Meer




___________________________________________________________________________________
If your question is of interest to others as well, please add an entry to the Wiki!

maillist : ntg-context@ntg.nl / http://www.ntg.nl/mailman/listinfo/ntg-context
webpage  : http://www.pragma-ade.nl / http://context.aanhet.net
archive  : https://bitbucket.org/phg/context-mirror/commits/
wiki     : http://contextgarden.net
___________________________________________________________________________________


met vriendelijke groet
dr. Hans van der Meer