On Sat, 1 Aug 2015, Eric Détrez wrote:

> Here is a minimal example :
>
> \usemodule[tikz]
> \starttext
> \noheaderandfooterlines
> \starttikzpicture
>   \draw(0,2) node[color=red]{This should be red};
>   \draw(0,0) node[color=red]{This is red};
> \stoptikzpicture
> \stoptext
>
> The first line is written in black
> but when I comment \noheaderandfooterlines both lines are red
>
> This seems a curious effect

Using \forcecolorhack works for this example:

\starttikzpicture
   \forcecolorhack
    \draw(0,2) node[color=red]{This should be red};
    \draw(0,0) node[color=red]{This is red};
\stoptikzpicture

Aditya