thx for your infirmation. I guess it doesn't give me the result. I understood that this expression works fine if I use that to format a dimension directly.
Th idea is to implement the color directly in the expression that the result comes back in the requested color like:
=if(( NetWorkDays( ( E_WE_Pos.c_Liefertermin), (E_WE_Pos.c_WE_Datum))-1) >2 ,
green() 'in time' )
I tried the a.m. version but it doesn't work in theis direction.