Hi Hans, I noticed that in some situations the command \thematrix does not show all its arguments correctly: some parts are omitted in the typeset formula. In some occasions adding some groupings solves the issue, but not always. I noticed this bug two weeks ago, but could not produce a minimal example until now… Please see below, in particular the output for the matrices M_1, M_2 and M_3… Best regards: Otared % begin bug-thematrix.tex \starttext \startformula M_{1}(t) := \thematrix{{\rm e}^s ; {\rm e}^t}, \qquad B_{1}(t) := \thematrix{1 , {\rm e}^t}, \stopformula \startformula M_{2}(t) := \thematrix{{{\rm e}^s} , {{\rm e}^t}}, \qquad B_{2}(t) := \thematrix{0 ; {{\rm e}^t}}, \stopformula \startformula M_{3}(t) = \thematrix{{\rm e}^s, {\rm e}^t ; 0 , {\rm e}^t}. \stopformula \startformula M_{4}(t) = \thematrix{1, {{\rm e}^t} + 1 ; 0 , {{\rm e}^t}}. \stopformula \stoptext % end bug-thematrix.tex