The MWE:
\documentclass{article}
\usepackage{xcolor}
\usepackage{colortbl}
\begin{document}
\setlength{\tabcolsep}{0pt}
\begin{tabular}{|c|c|@{}p{0pt}@{}}
\hline
\rowcolor{cyan!70!black}
Dummy & Text & \\[1em]
\hline
\end{tabular}
\end{document}
For some reason, I had to add a blank column at the end of the table, say @{}p{0pt}@{}. However, this behavior made the package colortbl sick. The width of the colored row didn't match the actual width of that row.
I searched TeX.SX and got a similar Q&A. In the answer to that question, David Carlisle, the author of the package colortbl, suggests that \tabcolsep could be set to 0pt and using >{\hspace{}} and <{\hspace{}}, from the package array, to insert extra space between columns.
Is there any better way to fix this problem (or both the two problems)? Any suggestion and/or clue would be appreciated.
mcolumns, and you would not want the first@{}in that case. Currently if you use@{}anywhere then the workaround that yor refer to is probably all there is unless someone wants to suggest a patch to colortbl. For the alignment problem Frank posted an answer here with a modifiedmcolumn that avoided the issue, I'll post a link if I find it. – David Carlisle Dec 04 '14 at 14:19