Why is text turning white (possible scope leak?) after page break and listings + tcolorbox + xelatex?

Question

I had a very difficult time pinning this problem down, because it only exists when certain page-breaking conditions occur.

Problem

Text after environment mysteriously turns white under some conditions.

Hypothesis

When embedded listings code within a tcolorbox, it is possible that the scope is lost when a page break should occur that would split that environment, but instead of page breaking, LaTeX reaches a certain penalty such that LaTeX decides to keep the environment on one page.

I have no idea how to diagnose this issue.

Let me illustrate the problem.

Code with expected Output

This code works fine.

\documentclass{article}
\usepackage{fontspec}%compile with xelatex
\usepackage{listings}%for mylstcode
\usepackage{xparse}%for latex3 NewDocumentEnvironemnt
\usepackage[most]{tcolorbox}% for newtcolorbox and colorlet
\lstnewenvironment{mylstcode}[1][]{\lstset{#1,basicstyle=\ttfamily,columns=fullflexible,keepspaces=true,basewidth=0.5em,breaklines=true}}{} % for general code
\NewDocumentEnvironment{myexample}{ O{} O{} }
{
\colorlet{colexam}{blue!50!black} % The maximal total height of the upper and of the lower part of normal breakable tcolorboxes is about 65536pt (ca. 2300cm).
\newtcolorbox[]{myexamplebox}{%
    % Example Frame Start
    empty,% Empty previously set parameters
    title={Example: #1},% use \thetcbcounter to access the ithexample counter text
    % Attaching a box requires an overlay
  breakable=unlimited,
    attach boxed title to top left,
  % Ensures proper line breaking in longer titles
  minipage boxed title,
    % (boxed title style requires an overlay)
    boxed title style={empty,size=minimal,toprule=0pt,top=4pt,left=3mm,overlay={}},
    coltitle=colexam,fonttitle=\bfseries,
    before=\par\medskip\noindent,parbox=false,boxsep=0pt,left=3mm,right=0mm,top=2pt,breakable,pad at break=0mm,
    before upper=\csname @totalleftmargin\endcsname0pt, % Use instead of parbox=true. This ensures parskip is inherited by box.
    % Handles box when it exists on one page only
    overlay unbroken={\draw[colexam,line width=.5pt] ([xshift=-0pt]title.north west) -- ([xshift=-0pt]frame.south west); },
    % Handles multipage box: first page
    overlay first={\draw[colexam,line width=.5pt] ([xshift=-0pt]title.north west) -- ([xshift=-0pt]frame.south west); },
    % Handles multipage box: middle page
    overlay middle={\draw[colexam,line width=.5pt] ([xshift=-0pt]frame.north west) -- ([xshift=-0pt]frame.south west); },
    % Handles multipage box: last page
    overlay last={\draw[colexam,line width=.5pt] ([xshift=-0pt]frame.north west) -- ([xshift=-0pt]frame.south west); },%
  #2
    }
\begin{myexamplebox}}
{\end{myexamplebox}\endlist}
\begin{document}
\begingroup
\obeylines
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\endgroup
%\vspace{-1ex} % Forcefully squeeze the two environments together
\begin{myexample}[for i in \{1..40\}; do echo \$i; done]
\begin{mylstcode}
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\end{mylstcode}
\end{myexample}
Here is a sentence that turns white.

Here is a sentence that turns white.

Here is a sentence that turns white.

Here is a sentence that turns white.
\end{document}

Output

Code with unexpected output

Note that the only change is uncommenting \vspace{-1ex}

This typesets, but please examine the sentences below \end{myexample}. You should notice that the text below the page break becomes white!

\documentclass{article}
\usepackage{fontspec}%compile with xelatex
\usepackage{listings}%for mylstcode
\usepackage{xparse}%for latex3 NewDocumentEnvironemnt
\usepackage[most]{tcolorbox}% for newtcolorbox and colorlet
\lstnewenvironment{mylstcode}[1][]{\lstset{#1,basicstyle=\ttfamily,columns=fullflexible,keepspaces=true,basewidth=0.5em,breaklines=true}}{} % for general code
\NewDocumentEnvironment{myexample}{ O{} O{} }
{
\colorlet{colexam}{blue!50!black} % The maximal total height of the upper and of the lower part of normal breakable tcolorboxes is about 65536pt (ca. 2300cm).
\newtcolorbox[]{myexamplebox}{%
    % Example Frame Start
    empty,% Empty previously set parameters
    title={Example: #1},% use \thetcbcounter to access the ithexample counter text
    % Attaching a box requires an overlay
  breakable=unlimited,
    attach boxed title to top left,
  % Ensures proper line breaking in longer titles
  minipage boxed title,
    % (boxed title style requires an overlay)
    boxed title style={empty,size=minimal,toprule=0pt,top=4pt,left=3mm,overlay={}},
    coltitle=colexam,fonttitle=\bfseries,
    before=\par\medskip\noindent,parbox=false,boxsep=0pt,left=3mm,right=0mm,top=2pt,breakable,pad at break=0mm,
    before upper=\csname @totalleftmargin\endcsname0pt, % Use instead of parbox=true. This ensures parskip is inherited by box.
    % Handles box when it exists on one page only
    overlay unbroken={\draw[colexam,line width=.5pt] ([xshift=-0pt]title.north west) -- ([xshift=-0pt]frame.south west); },
    % Handles multipage box: first page
    overlay first={\draw[colexam,line width=.5pt] ([xshift=-0pt]title.north west) -- ([xshift=-0pt]frame.south west); },
    % Handles multipage box: middle page
    overlay middle={\draw[colexam,line width=.5pt] ([xshift=-0pt]frame.north west) -- ([xshift=-0pt]frame.south west); },
    % Handles multipage box: last page
    overlay last={\draw[colexam,line width=.5pt] ([xshift=-0pt]frame.north west) -- ([xshift=-0pt]frame.south west); },%
  #2
    }
\begin{myexamplebox}}
{\end{myexamplebox}\endlist}
\begin{document}
\begingroup
\obeylines
1
1
1
1
\endgroup
\vspace{-1ex} % Forcefully squeeze the two environments together
\begin{myexample}[for i in \{1..40\}; do echo \$i; done]
\begin{mylstcode}
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\end{mylstcode}
\end{myexample}
Here is a sentence that turns white.

Here is a sentence that turns white.

Here is a sentence that turns white.

Here is a sentence that turns white.
\end{document}

Note to Christian Hupfer: I know you do not like when I wrap tcolorbox with a \NewDocumentEnvironment :)

Answer 1

There's some strange interaction between listings wrapped in a tcolorbox and xelatex. I recommend to use a special \newtcblisting and use this (in the outer wrapper, if really needed ;-))

In this case the text does not vanish, regardless whether it is compiled with pdflatex, xelatex or lualatex.

\documentclass{article}
\usepackage{fontspec}%compile with xelatex
\usepackage{xparse}%for latex3 NewDocumentEnvironemnt
\usepackage[most]{tcolorbox}% for newtcolorbox and colorlet

\lstnewenvironment{mylstcode}[1][]{\lstset{#1,basicstyle=\ttfamily,columns=fullflexible,keepspaces=true,basewidth=0.5em,breaklines=true}}{} % for general code

\newtcblisting{myexamplelisting}[3][]{%
  listing only,
  listing options={#1,basicstyle=\ttfamily,columns=fullflexible,keepspaces=true,basewidth=0.5em,breaklines=true},
  empty,% Empty previously set parameters
  title={Example: #2},% use \thetcbcounter to access the ithexample counter text
  % Attaching a box requires an overlay
  breakable,%=unlimited,
  attach boxed title to top left,
  % Ensures proper line breaking in longer titles
    minipage boxed title,
    % (boxed title style requires an overlay)
    boxed title style={empty,size=minimal,toprule=0pt,top=4pt,left=3mm,overlay={}},
    coltitle=colexam,fonttitle=\bfseries,
    before=\par\medskip\noindent,parbox=false,boxsep=0pt,left=3mm,right=0mm,top=2pt,breakable,pad at break=0mm,
    before upper=\csname @totalleftmargin\endcsname0pt, % Use instead of parbox=true. This ensures parskip is inherited by box.
    % Handles box when it exists on one page only
    overlay unbroken={\draw[colexam,line width=.5pt] ([xshift=-0pt]title.north west) -- ([xshift=-0pt]frame.south west); },
    % Handles multipage box: first page
    overlay first={\draw[colexam,line width=.5pt] ([xshift=-0pt]title.north west) -- ([xshift=-0pt]frame.south west); },
    % Handles multipage box: middle page
    overlay middle={\draw[colexam,line width=.5pt] ([xshift=-0pt]frame.north west) -- ([xshift=-0pt]frame.south west); },
    % Handles multipage box: last page
    overlay last={\draw[colexam,line width=.5pt] ([xshift=-0pt]frame.north west) -- ([xshift=-0pt]frame.south west); },%
    #3%
}

\NewDocumentEnvironment{myexample}{ O{} O{} }
{%
  \colorlet{colexam}{blue!50!black} % The maximal total height of the upper and of the lower part of normal breakable tcolorboxes is about 65536pt (ca. 2300cm).
  \myexamplelisting{#1}{#2}%
}
{\endmyexamplelisting\endlist}
\begin{document}
\begingroup
\obeylines
1
1
1
1
\endgroup
\vspace{-1ex} % Forcefully squeeze the two environments together
\begin{myexample}[for i in \{1..40\}; do echo \$i; done]
\begin{mylstcode}
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\end{mylstcode}
\end{myexample}
Here is a sentence that turns white.

Here is a sentence that turns white.

Here is a sentence that turns white.

Here is a sentence that turns white.
\end{document}

Answer 2

Update 2016-09-16

Thomas F. Sturm mentions in the question comment that this problem may no longer exist, possibly due to a change in xelatex, but not due to a change in tcolorbox.

---

Solution until Compatibility Fix

In your Preamble add the following line to explicitly reset the font color to black after each tcolorbox:

• \AfterEndEnvironment{myexample}{\color{black}}

Embedding tcolorbox within a list will negate the aforementioned fix outside of the list's scope. Therefore also add the following:

• \AfterEndEnvironment{itemize}{\color{black}}
• \AfterEndEnvironment{enumerate}{\color{black}}
• \AfterEndEnvironment{description}{\color{black}}

Loading xcolor explicitly calls \color{black}.

Update 2016-05-12: Instead of explicitly setting "black", you could use \AtBeginDocument{\colorlet{defaultcolor}{.}} to make a defaultcolor colorlet that can be used after each myexample environment to restore the default color--at least until the packages/compiler work in harmony someday. See answers at xcolor - What is the equivalent of default text color?

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Related Questions

• How do I get fontspec to work with text color white in XeLaTeX
• Last xe(la)tex colors text in white in some circumstances
• xelatex and tcolorbox incompatibility?
• https://tex.stackexchange.com/questions/287580/does-tcolorbox-3-11-have-a-problem-with-page-breaks-causing-invisible-text-whit

---

mdframed Approach

Note this has a deal-breaker limitation

It has the disadvantage that the embedded listings environment does not properly break over pages.

Also, I've had about as much grief as I can handle with the listings package. It seems to frequently cause mysterious character issues.

\documentclass{article}
\usepackage{fontspec}% typeset with xelatex
\usepackage{tikz}
\usetikzlibrary{calc}
\usepackage[framemethod=tikz]{mdframed} % Add easy frames to paragraphs
\usepackage{xparse}
\usepackage{listings}
\lstnewenvironment{mylstcode}[1][]{\lstset{#1,basicstyle=\ttfamily,columns=fullflexible,keepspaces=true,basewidth=0.5em,breaklines=true}}{} % for general code
\mdfdefinestyle{exampledefault}{%
hidealllines=true,
linecolor=blue!20!black,
fontcolor=blue!20!black,
rightline=false,
leftline=true,
bottomline=false,
topline=false,
innerleftmargin=10pt,innerrightmargin=10,
frametitlerule=false,
frametitlerulecolor=blue!20!black,
frametitlebackgroundcolor=white,
frametitlerulewidth=1pt,
 firstextra={\path let \p1=(P), \p2=(O) in ($(\x2,0)+0.5(0,\y1)$)
                           node[] {};},%
 secondextra={\path let \p1=(P), \p2=(O) in ($(\x2,0)+0.5(0,\y1)$)
                           node[] {};},%
 middleextra={\path let \p1=(P), \p2=(O) in ($(\x2,0)+0.5(0,\y1)$)
                           node[] {};},%
 singleextra={\path let \p1=(P), \p2=(O) in ($(\x2,0)+0.5(0,\y1)$)
                           node[] {};},%
}
\NewDocumentEnvironment{myexample}{ O{} O{} }
{\begin{mdframed}[style=exampledefault,frametitle={Example: #1}]}
{\end{mdframed}}
\begin{document}
\begin{myexample}[for i in {1..40}; do echo $i; done]
\begin{mylstcode}
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\end{mylstcode}
\end{myexample}
\end{document}