Hello Hans, The following code compiles fine with MikTeX (version 2006.08.22), but fails with a recent beta: \def\room#1{\starttable[ s0 |r|l|]#1\stoptable} \def\student#1#2{\NC#1\NC#2\NC\MR} \starttext \room{ \student{A}{B} \student{C}{D} } \stoptext I get the following error: ! Undefined control sequence. \dotextmodediscretionary ...up \let \nextnextnext \egroup \def \next ##1#1{\... <argument> s0 | r|l| \doifsomething #1->\edef \!!stringa {#1 }\ifx \!!stringa \empty \expandafter ... \thirdstagestartTABLE ...etall \doifsomething {#1} {\def \TABLEformat {#1}\g... \dorestartTABLE ...restartTABLE {#1}\restartTABLE \TABLEnoalign {\globalpush... \room #1->\starttable [ s0 |r|l|] #1\stoptable l.9 } ? ! Emergency stop. Mojca