Dear list,

I have an error when I try to insert a block inside a conditional mode (but there is two nested conditional mode.. is this the problem ?).  

In my courses notes, I insert some blocks (named «  Complement » in the minimal exemple below) when in « Professor » mode. This works fine, as shown in the first «  \beginComplement … \endComplement  » of my example below. 

But now I have to use another condition for some blocks, depending of the number of the current course. So I insert my block with a condition, here « CourseOne » :

	\enablemode[CourseOne]
	\doifmode{CourseOne}{
		\beginComplement
		Another complementary slide. 
		\endComplement
	}

But this does not work :

% ————
tex error       > tex error on line 1 in file /Users/fabricel/context/tex/texmf-context/tex/context/base/mkiv/cont-yes.mkiv: ! TeX capacity exceeded, sorry [input stack size=50000]
% ————

The problem can be summarized in this minimal non working example : 

% — MWE —————————————————————
\setuppapersize[S5][S5]
\enablemode[Professor]

\defineblock[Complement]
\setupblock[Complement][
	before={\page[yes]\setuppagenumber[state=stop]\setupheadertexts[]\setupbackgrounds[page][background=color,backgroundcolor=red]},
	after={\page[yes]\setuppagenumber[state=start]}]
\doifallmodes{Professor} {
    \keepblocks[Complement]
}

\starttext

	page 1
	
	\beginComplement
		A complementary slide. 
	\endComplement

	page 2

	\enablemode[CourseOne]
	\doifmode{CourseOne}{
		\beginComplement
		Another complementary slide but only for course number 1. 
		\endComplement
	}
	\disablemode[CourseOne]

	page 3

	\enablemode[CourseTwo]
	\doifmode{CourseTwo}{
		\beginComplement
		Another complementary slide but only for course number 2. 
		\endComplement
	}
	\disablemode[CourseTwo]

\stoptext
\stoptext

% — MWE —————————————————————

Blocks and modes usually works fine for me, but here, I do not understand my error.
Thanks for any help ! 

Fabrice. 


Note : in case this way of doing things seems a bit silly, here are more explanations. I do use mode « CourseOne »  here because in the real life, the content in the condition «  \doifmode{CourseOne}{ …} » is read in an external file, containing material for « CourseOne », « CourseTwo », etc. The setup is then, in the main file :

% Main file : begin ----------------

Bla bla bla ...

\enablemode[CourseOne]
\input ComplementMaterial.tex
\disablemode[CourseOne]

Bla bla bla ...

\enablemode[CourseOne]
\input ComplementMaterial.tex
\disablemode[CourseOne]

% Main file : end ----------------

And in the « ComplementMaterial.tex » there is :

% ComplementMaterial.tex —————————

	\doifmode{CourseOne}{
		\beginComplement
		A complementary slide but only for course number 1. 
		\endComplement

		\beginComplement
		Another complementary slide but only for course number 1. 
		\endComplement
	}

	\doifmode{CourseTwo}{
		\beginComplement
		A complementary slide but only for course number 2. 
		\endComplement

		\beginComplement
		Another complementary slide but only for course number 2. 
		\endComplement
	}
% ComplementMaterial.tex —————————