table cell shading overlaps to nearby cells

Question

I have a latex table as follows

\documentclass[12pt]{report}

\usepackage{colortbl}

\begin{document}

\begin{table}
\centering
\begin{tabular}{|@{\,}c@{\,}|@{\,}c@{\,}|@{\,}c@{\,}|@{\,}c@{\,}|}
\hline
Column1 & Column2 & Column3 & Column4 \\
\hline
A & \cellcolor[gray]{0.5} & D & E \\
\hline
 &  &  & F \\
\hline
 &  &  & \\
\hline
\end{tabular}
\end{table}

\end{document}

The cell color is overlaping to the nearby columns. It may be because of @{\,} I used with tabular to remove text padding in columns(It is required since my actual table has more width). Anyone know how prevent the cell shading from overlapping to other cells in this case?

Answer 1

colortbl adds a padding \tabcolsep wide; instead of using @{\,} you should reduce \tabcolsep:

\documentclass[12pt]{report}

\usepackage{colortbl}

\begin{document}

\begin{table}
\centering
\setlength{\tabcolsep}{0.3em}
\begin{tabular}{|c|c|c|c|}
\hline
Column1 & Column2 & Column3 & Column4 \\
\hline
A & \cellcolor[gray]{0.5} & D & E \\
\hline
 &  &  & F \\
\hline
 &  &  & \\
\hline
\end{tabular}
\end{table}

\end{document}

Answer 2

For information, with {NiceTabular} of nicematrix (with the key color-inside --- alias: colortbl-like), you have directly the expected ouptut with your code.

However, as said by egreg, the good solution to your problem is to change \tabcolsep.

\documentclass[12pt]{report}
\usepackage{nicematrix}

\begin{document}

\begin{table}
\centering
\begin{NiceTabular}{|@{\,}c@{\,}|@{\,}c@{\,}|@{\,}c@{\,}|@{\,}c@{\,}|}[color-inside]
\hline
Column1 & Column2 & Column3 & Column4 \\
\hline
A & \cellcolor[gray]{0.5} & D & E \\
\hline
 &  &  & F \\
\hline
 &  &  & \\
\hline
\end{NiceTabular}
\end{table}

\end{document}

You need several compilations.