Hi all, today's beta introduced a really strange problem. Consider two source files: definitions.tex: \startmodule[definitions] \def\lambdax{\lambda_x} \stopmodule[definitions] main.tex: \usemodule[definitions] \starttext blah $\lambdax$ blah. \stoptext This results in the following compile error: ! Undefined control sequence. \lambdax ->\lambda_x l.5 blah $\lambdax $ blah. ? However, if you change "\usemodule[definitions]" into "\input definitions" instead, then there is no compile error! My understanding is that the underscore is a valid character for macro names now outside of math mode, which is what is causing the problem. But I really don't understand what magic is going on in the modules code to trigger this. I would be very interested in an explanation of what is going on. Many thanks, Mathieu