Highlighting code introduces extra space

Question

I am trying to highlight portions of code inside a listings environment. However, using tikz introduces some extra spaces that I do not understand and would like to ask how I can rid of them.

Here is a small document that shows my problem:

\documentclass[10pt,a4paper,twoside,openright,titlepage,abstracton]{scrreprt} %report}
\usepackage{listings}
\lstset{language=Java,escapechar=!}

\usepackage{tikz}
\newcommand\eh{\tikz[remember picture]\node (end highlight){};\tikz[remember picture, overlay]\draw[yellow,line width=10pt,opacity=0.3](begin highlight)--(end highlight);}
\newcommand{\bh}{\tikz[remember picture]\node(begin highlight){};}


\begin{document}
\begin{lstlisting}
Lol rofl roflcopter
\end{lstlisting}
\begin{lstlisting}
Lol !\bh!rofl!\eh! roflcopter
\end{lstlisting}
\end{document}

Although I expected it to be yellow, you get the point: rofl has more spacing when highlighted :

Answer 1

Instead of \nodes you can use \coordinates which don't introduce extra spacing:

\documentclass[10pt,a4paper,twoside,openright,titlepage,abstracton]{scrreprt} %report}
\usepackage{listings}
\lstset{language=Java,escapechar=!}

\usepackage{tikz}

\newcommand\eh{%
\tikz[remember picture,overlay]{
  \coordinate (end highlight){};%
  \draw[yellow,line width=10pt,opacity=0.3]
    ([yshift=.9ex]begin highlight) -- ([yshift=.9ex]end highlight);}%
}
\newcommand{\bh}{%
  \tikz[remember picture]\coordinate(begin highlight){};}

\begin{document}
\begin{lstlisting}
Lol rofl roflcopter
\end{lstlisting}
\begin{lstlisting}
Lol !\bh!rofl!\eh! roflcopter
\end{lstlisting}
\end{document}

Answer 2

If you use use the overlay option, you don't get any additional horizontal space introduced. So,

\newcommand\eh{%
    \tikz[remember picture, overlay] \node (end highlight){};%
    \tikz[remember picture, overlay]\draw[yellow,line width=10pt,opacity=0.3]
        (begin highlight)--(end highlight);%
}
\newcommand{\bh}{\tikz[remember picture, overlay] \node(begin highlight){};}

yields no additional spacing: