[NTG-context] Modes and conditional part of the source

Hello, I'm struggling with using modes to make a part of the text conditional. Here is my code: ---- \def\b#1{\startmode[#1]} \def\e{\stopmode} % \enablemode[100] % For optional usage \starttext A \b{100} % Should be start of some conditional text from here ... B \e % ... to here \stoptext ---- Compilation fails with: " tex error > tex error on line 0 in file : ! Emergency stop <*> cont-yes.mkiv <empty file> *** (job aborted, no legal \end found) " How to make the sample work? Best regards, Lukas -- Ing. Lukáš Procházka | mailto:LPr@pontex.cz Pontex s. r. o. | mailto:pontex@pontex.cz | http://www.pontex.cz | IDDS: nrpt3sn | IČO: 40763439 Bezová 1658 147 14 Praha 4 Mob.: +420 702 033 396