paragraph spacing goes awry when tcolorbox is inside wrapfigure

Question

I have a tcolorbox environment that I use on its own, and sometimes inside a wrapfigure. On its own, it works perfectly - paragraphs are spaced according to my document's parskip and parindent. However, inside wrapfigure those settings seem to be ignored.

Here is a MWE:

% !TEX program = xelatex

\documentclass{scrbook}

\usepackage{wrapfig}
\usepackage{graphicx}
\usepackage{tcolorbox}

\setlength{\parskip}{3mm}
\setlength{\parindent}{0pt}

\newtcolorbox[auto counter]{sidebar}[2][]{
    parbox=false, % normal paragraph spacing (unless wrapped!)
    sharp corners,
    colframe=black,
    colback=black!15!white,
    title=#2,
    #1
}

\begin{document}

\begin{sidebar}{Test without wrapping}
    Paragraph 1.

    Paragraph 2.
\end{sidebar}

\begin{wrapfigure}{r}{0.5\linewidth}
    \begin{sidebar}{Test with wrapping and no explicit parksip}
        Paragraph 1.

        Paragraph 2.
    \end{sidebar}
\end{wrapfigure}

\begin{wrapfigure}{r}{0.5\linewidth}
    \begin{sidebar}{Test with wrapping and explicit parskip}
        \setlength{\parskip}{3mm}\setlength{\parindent}{0pt}Paragraph 1.

        Paragraph 2.
    \end{sidebar}
\end{wrapfigure}

\end{document}

Here is the output:

Is there any way I can avoid the need to explicitly specify parskip (and parindent) inside my wrapped tcolorbox?

Answer 1

Note that you should use the parskip class option with KOMA classes, rather than parskip or, worse, setting the dimensions manually. If the default parskip isn't appropriate, see KOMA's documentation for the various values you can set it to.

You can restore the required skip using the hooks library. For example,

\documentclass[parskip]{scrbook}
\usepackage{wrapfig}
\usepackage{graphicx}
\usepackage{tcolorbox}
\tcbuselibrary{hooks}
\usepackage{kantlipsum}
\newlength\myskip
\AtBeginDocument{%
  \setlength\myskip{\parskip}%
}
\newtcolorbox[auto counter]{sidebar}[2][]{
  parbox=false, % normal paragraph spacing (unless wrapped!)
  sharp corners,
  colframe=black,
  colback=black!15!white,
  before upper app={\par\parskip=\myskip},
  title=#2,
  #1
}

\begin{document}

\begin{sidebar}{Test without wrapping}
  Paragraph 1.

  Paragraph 2.
\end{sidebar}

\begin{wrapfigure}{r}{0.5\linewidth}
  \begin{sidebar}{Test with wrapping and no explicit parksip}
    Paragraph 1.

    Paragraph 2.
  \end{sidebar}
\end{wrapfigure}
\kant[1]

\begin{wrapfigure}{r}{0.5\linewidth}
  \begin{sidebar}{Test with wrapping and explicit parskip}
    \setlength{\parskip}{3mm}\setlength{\parindent}{0pt}Paragraph 1.

    Paragraph 2.
  \end{sidebar}
\end{wrapfigure}
\kant[2]

\end{document}