On 11/17/2016 11:21 AM, Christoph Reller wrote:
> Hi,
>
> I have the following minimal not-working example:
>
> \starttext
> \startitemize
> \item One
>   \startmode[modeA]
>   \item Two
>     \startitemize
>       \startmode[modeB] % <- this
>       \item Two A       % <- does
>       \stopmode         % <- not work
>       % \doifmode{modeB}{\item Two A} % <- this works
>     \item Two B
>     \stopitemize
>   \stopmode
> \stopitemize
> \stoptext
>
> Note that both modeA and modeB are not defined and hence not enabled.
> When compiled with the latest version of ConTeXt MkIV, I get: Missing
> number, treated as zero.
> However, If I use the inline version \doifmode instead of the
> environment version \startmode \stopmode, then the example compiles
> without problem.
>
> I am afraid but this may be a bug.

No, just the way tex parses, \stopmode is a delimiter so the inner
\stopmode ends the outer \startmode.

Using the \doif variable doesn't have that problem.