I have defined a determinant environment like below: \definemathmatrix[determinant] [matrix:bars] [simplecommand=thedeterminant] and I create a determinant like below: \startformula \startdeterminant\NC a_{11} \NC a_{12} \NC a_{13} \NC \cdots \NC a_{1n}\NR \NC a_{21} \NC a_{22} \NC a_{23} \NC \cdots \NC a_{2n}\NR \NC a_{31} \NC a_{32} \NC a_{33} \NC \cdots \NC a_{3n}\NR \multispan{9}{\dotfill}\NR \NC a_{n1} \NC a_{n2} \NC a_{n3} \NC \cdots \NC a_{nn} \NR\stopdeterminant This was working before today but I updated ConTeXt and it has stopped working. The error it gives me now is: tex error > tex error on line 277 in file determinants.tex: You can't use '\Ustopmath' in restricted horizontal mode How can I get it working again? -- Respect, Shiv Shankar Dayal