Hi, the \begingroup and \endgroup commands are not possible here because they are the delimiters for the \hbox. \def\doalignline#1#2% \\ == newline {\noindentation % was \noindent \dontleavehmode % added in marrakesch at TUG 2006\begingroup \begingroup \setlocalhsize % new - \def\\{\endgroup\par\doalignline{#1}{#2}\begingroup}% + \def\\{\egroup\par\doalignline{#1}{#2}\bgroup}% \dowithnextbox {\hbox to \localhsize {\ifcase\alignstrutmode\or\strut\fi \the\everyleftofalignedline #1\unhbox\nextbox#2\relax \the\everyrightofalignedline}% \endgroup} \hbox} \def\doxalignline#1#2#3#4#5#6% {\noindentation % was \noindent \dontleavehmode % added in marrakesch at TUG 2006\begingroup \begingroup \setlocalhsize - \def\\{\endgroup\par\doxalignline#1#2#3#4#5#6\begingroup}% inefficient + \def\\{\egroup\par\doxalignline#1#2#3#4#5#6\bgroup}% inefficient \dowithnextbox {\hbox to \localhsize {#1\hskip\ifdone#2\else#3\fi#4% \hbox to \localhsize {\the\everyleftofalignedline \ifcase\alignstrutmode\or\strut\fi \ifdone#5\unhbox\nextbox#6\else#6\unhbox\nextbox#5\fi \the\everyrightofalignedline}% \hss}% \endgroup} \hbox} Wolfgang