How to prevent pagebreaks between section/subsection titles and the multicolumn content of the document when using the paracol environment like this...
\renewcommand{\deutschertitel}{Dezimalsystem}
\renewcommand{\englischertitel}{Decimal System}
\subsection[\englischertitel]{}
\begin{paracol}{2}[]
\subsection*{\englischertitel}
\switchcolumn
\subsection*{\deutschertitel}
\switchcolumn*
The decimal system uses...
\switchcolumn
Das Dezimalsystem verwendet...
\end{paracol}
Here is one example that shows a page break where it should not happen:
Another example that shows a page break where it should not happen:
Update (2019-01-23):
Added a better source code example and some screenshots that show the issue.