Hi Hans, with the beta 2011.01.26 11:02 and the attached example (tooltip.tex) compilation break with [..] javascript : loading script set fld ! LuaTeX error r:/tex/texmf-context/tex/context/base/supp-fil.lua:322: attempt to call local 'failure' (a nil value) stack traceback: r:/tex/texmf-context/tex/context/base/supp-fil.lua:322: in function 'uselibrary' r:/tex/texmf-context/tex/context/base/java-ini.lua:151: in function 'usescripts' <main ctx instance>:1: in main chunk. \douseJSscripts ...pts.usescripts(\!!bs #1\!!es )} \douseJSpreamblenow {#2} <to be read again> \globallet \loadfieldscripts ->\useJSscripts [fld]\globallet \loadfieldscripts \relax \doprocessfield ... \begingroup \loadfieldscripts \edef \currentfieldname {#... <to be read again> } \dotooltip ...fitfield [\currentsystemfield :txt]} }\dimen 0=\ifdim \wd 0=\ze... l.5 \tooltip{\CONTEXT}{a \TEX\ macropackage} ? mkii works, but I get black text on black background for the tooltip. Best wishes, Peter