Hi, I have a broken flow cell connection in this minimal example. The broken flow cell is only triggered when drawn within a subsection with an overlay. The logic to create the underlined subsection is by the way copied from the metafun manual source. I do not have the slightest clue what is going wrong in this example. Thanks for ideas. Best, Bernd \usemodule[chart] \startuniqueMPgraphic{SectionUnderline} path p; p:= unitsquare xscaled OverlayWidth yscaled OverlayHeight; draw llcorner p -- lrcorner p; setbounds currentpicture to p; \stopuniqueMPgraphic \defineoverlay[SectionUnderline][\uniqueMPgraphic{SectionUnderline}] \starttexdefinition unexpanded ChapterCommand #1#2 \framed [background=SectionUnderline] {#2} \stoptexdefinition \setuphead [subsection] [command=\ChapterCommand] \starttext \subsection[title=Introduction] \startFLOWchart[toolchain] \startFLOWcell \location{1,1} \connection [bt] {compiler} \stopFLOWcell \startFLOWcell \name {compiler} \location{1,2} \shape{product} \stopFLOWcell \stopFLOWchart \FLOWchart[toolchain] \stoptext