Hi Hans, below is a simple patch for a error which is generated by the example at the end of the mail. \unexpanded\def\strc_formulas_start_formula_indeed[#1][#2]% setting leftskip adaption is slow ! {\bgroup % HERE \def\currentformula{#1}% \dostarttaggedchained\t!formula\currentformula\??formula \the\everybeforedisplayformula \setfalse\c_strc_formulas_tight %\formulastrutdp\strutdepth %\formulastrutht\strutheight \d_strc_formulas_display_skip_left \leftskip \d_strc_formulas_display_skip_right \rightskip \d_strc_formulas_display_width \formulaparameter\c!width\relax \d_strc_formulas_display_margin_left \formulaparameter\c!leftmargin \relax \d_strc_formulas_display_margin_right\formulaparameter\c!rightmargin\relax \edef\p_option{\formulaparameter\c!option}% - \edef\p_option{\ifx\p_option\empty\else\p_option,\fi#2}% + \ifsecondargument + \edef\p_option{\ifx\p_option\empty\else\p_option,\fi#2}% + \fi \ifx\p_option\empty \else \rawprocesscommacommand[\p_option]\strc_formulas_option \fi \edef\p_margin{\formulaparameter\c!margin}% \ifx\p_margin\empty \else \dosetleftskipadaption\p_margin \d_strc_formulas_display_margin_left\leftskipadaption \fi \let\strc_formulas_start_formula\strc_formulas_start_formula_nested \strc_formulas_forget_display_skips \csname\e!start\formulaparameter\c!alternative\v!formula\endcsname} %% begin example \defineformula[pagella][option=pagella] \starttext % this works %\startformula[pagella] % c^2 = a^2 + b^2 %\stopformula % this doesn’t \startpagellaformula c^2 = a^2 + b^2 \stoppagellaformula \stoptext %% end example Wolfgang