backgroundscreen is broken. minimal example: \starttext \setupbackgrounds [page] [background=screen,backgroundscreen=.65] Some text. \stoptext ! LuaTeX error <main ctx instance>:1: unexpected symbol near ')'. \dosetrastercolor ..."_raster_",\@@rastervalue ))} \BeforeGroup ...medparameter \c!backgroundscreen } \bgroup \aftergroup \After... <argument> ...amedparameter \c!backgroundscreen ]{ \dofilledbox } \secondoftwoarguments #1#2->#2 \dodobackgroundbox ...urrentbackground \endcsname }}}\wd \extraframebox \zer... \dododobackgroundbox ... \else \dodobackgroundbox \expandafter \dododobackgr... ... l.6 \stoptext