Hi, in more recent versions of lmtx, the side-by-side mechanism appears to be broken; example below. The right-hand paragraph does not respect the margin and backspace setting. The output looks fine in mkiv and with older versions of lmtx (the one from texlive, so 2023.03.10). Not sure if this has been reported yet. All best Thomas \setuppapersize[A4,landscape] \setuplayout[height=fit, width=middle, header=0cm, footer=0cm, leftmargin=2cm, topspace=1.2cm, backspace=1.5cm] \showframe \defineparagraphs[Half] [n=2] \setupparagraphs [Half] [before=,after=,distance=3em,align={normal,hanging},tolerance={stretch,verytolerant}] \setupparagraphs [Half] [1] [width=0.43\textwidth,tolerance={stretch,verytolerant}] \setupparagraphs [Half] [2] [rulethickness=2mm,rulecolor=gray,rule=on,tolerance={stretch,verytolerant}] \starttext \startHalf \input ward \nextHalf \input knuth \stopHalf \stoptext