Dear list, I have the following sample: \startluacode function document.addfunnyhyphen(tfmdata) local underscore = utf.byte("_") local char = tfmdata.characters[underscore] tfmdata.characters[0xFE000] = { width = 0, height = 0, depth = 0, commands = { { "right", -char.width }, { "down", char.depth }, { "slot", 1, underscore }, } } end utilities.sequencers.appendaction("aftercopyingcharacters","after","document.addfunnyhyphen") \stopluacode \def\CoverImageFile{}%\externalfigure[TypeWriter][width=\textwidth]} \definefontfamily[ornamenta][rm][FontAwesome] \def\CoverImageFont{\scale[width=\textwidth]{\ornamenta }} \def\CoverImage{\doifsomethingelse{\CoverImageFile}{\CoverImageFile}{\CoverImageFont}} \starttext \CoverImage \stoptext For some reason unknown to me, the only way to compile the sample is to remove the luacode snippet. I need the lua code to have underscore hyphenation in type commands. And I need two extra \definehyphenationfeatures and \sethyphenationfeatures to invoke it. Have I hit a bug or what am I missing? Many thanks for your help, Pablo -- http://www.ousia.tk