\documentclass[a4paper,10pt]{article}
\usepackage[framemethod=TikZ]{mdframed}
\usepackage{lipsum}
\usepackage{multicol}
\mdfdefinestyle{graybox}{
splittopskip=0,%
splitbottomskip=0,%
frametitleaboveskip=0,
frametitlebelowskip=0,
skipabove=0,%
skipbelow=0,%
leftmargin=0,%
rightmargin=0,%
innertopmargin=2mm,%
innerbottommargin=2mm,%
roundcorner=2mm,%
backgroundcolor=gray!20}
\begin{document}
\begin{mdframed}[style=graybox]
\begin{multicols}{2}
\lipsum[1]
\columnbreak
\lipsum[2]
\end{multicols}
\end{mdframed}
\end{document}
Result:
How do I remove that top margin inside the mdframe?
Already tried this but doesn't work:
\begin{document}
\begin{mdframed}[style=graybox]
\begin{multicols}{2}
\vskip -2\baselineskip
\lipsum[1]
\columnbreak
\vskip -2\baselineskip
\lipsum[2]
\end{multicols}
\end{mdframed}
\end{document}