XeLaTeX Listings 包标签大小未正确显示

Question

我正在使用 XeLaTeX，并使用 listings 包来显示一些源代码。\lstset我将 tabsize 设置为 4：

\documentclass[a4paper, 11pt]{article}
\usepackage{filecontents}
\begin{filecontents*}{Text.txt}
public static int[] mergeSort(int[] array) {
    if (array.length == 1) {
        return array;
    }
    int[] left = new int[array.length / 2], right = new int[array.length - left.length];
    System.arraycopy(array, 0, left, 0, array.length / 2);
    System.arraycopy(array, left.length, right, 0, right.length);
    left = mergeSort(left);
    right = mergeSort(right);
    return merge(left, right);
}
\end{filecontents*}
\usepackage{listings}
\lstset{
backgroundcolor=\color{lightgray},
basicstyle=\ttfamily\color{darkgray},
keywordstyle=\ttfamily\color{darkgray},
caption=a,
commentstyle=\color{gray}\ttfamily,
showstringspaces=false,
flexiblecolumns=true,
tabsize=4,
showtabs=false,
xleftmargin=0pt,
xrightmargin = 0pt,
label=DescriptiveLabel,
breaklines=true,
breakatwhitespace=true,
language=JAVA
}}
\begin{document}
\lstinputlisting{Text.txt}
\end{document}

但是显示代码时的 tabsize 是 3。可能是什么问题？感谢您的帮助。