The MWE at the end of this mail typesets something like this:

* a      * e

* b      * f

* c

* d

But I'd expect something like this:

* a      * d

* b      * e

* c      * f

How can I get expected output?

```tex

\starttext

  \startcolumns[n=2]

    \startitemize

      \item a

      \item b

      \item c

      \item d

      \item e

      \item f

    \stopitemize

  \stopcolumns

\stoptext

```