Vertical centering thead in tabularx break when newline text in any column in row

Question

I have the following long table with tabularx.

\renewcommand\tabularxcolumn[1]{m{#1}}

\begin{tabularx}{\textwidth}{|>{\hsize=.25\hsize\centering\let\newline\\\arraybackslash}X|
    >{\hsize=.5\hsize\raggedright\let\newline\\\arraybackslash}X|
    >{\hsize=.25\hsize\centering\let\newline\\\arraybackslash}X|}
    \hline
    \thead{Thời gian}
    & \thead{Công việc}
    & \thead{Người thực hiện}
    \\
    \hline
    x/x/xx
    \newline
    -
    \newline
    x/x/xx
    &
    - Lorem Ipsum is simply dummy text of the printing and typesetting industry. Lorem Ipsum has been the industry's standard dummy text ever since the 1500s.
    \newline
    - Lorem Ipsum is simply dummy text of the printing and typesetting industry.
    &
    Lorem Ipsum is simply dummy
    \\
    \hline

\thead worked pretty well. I used \thead because I want texts in the header row centered and the content of the middle column to float left or \raggedright.

The problem comes here when I breaking line \\ to a random \thead like this:

\renewcommand\tabularxcolumn[1]{m{#1}}

\begin{tabularx}{\textwidth}{|>{\hsize=.25\hsize\centering\let\newline\\\arraybackslash}X|
    >{\hsize=.5\hsize\raggedright\let\newline\\\arraybackslash}X|
    >{\hsize=.25\hsize\centering\let\newline\\\arraybackslash}X|}
    \hline
    \thead{Thời gian}
    & \thead{Công việc}
    & \thead{Người \\ thực hiện}
    \\
    \hline
    x/x/xx
    \newline
    -
    \newline
    x/x/xx
    &
    - Lorem Ipsum is simply dummy text of the printing and typesetting industry. Lorem Ipsum has been the industry's standard dummy text ever since the 1500s.
    \newline
    - Lorem Ipsum is simply dummy text of the printing and typesetting industry.
    &
    Lorem Ipsum is simply dummy
    \\
    \hline

The FIRST and SECOND \thead column have changed their anchor and do not center veticaly anymore.

Can you show me how to fix this?

Answer 1

You don't really need to use the \thead command (from makecell). Here is a simplified version, and some improvements as to vertical spacing in cells, with the help of the cellspace package:

    \documentclass{article}
    \usepackage[vietnamese]{babel}
    \usepackage{tabularx}
    \usepackage{cellspace}
    \setlength{\cellspacetoplimit}{4pt}
    \setlength{\cellspacebottomlimit}{4pt}
    \addparagraphcolumntypes{X}
    \renewcommand\tabularxcolumn[1]{m{#1}}

    \begin{document}

        \begin{tabularx}{\textwidth}{|>{\hsize=.25\hsize\centering\let\newline\\\arraybackslash}X|
            >{\hsize=.5\hsize\raggedright\let\newline\\\arraybackslash}X|
            >{\hsize=.25\hsize\centering\let\newline\\\arraybackslash}S{X}|}
            \hline
            Thời gian
            & Công việc
            & Người \newline thực hiện
            \\
            \hline
        \end{tabularx}

    \end{document} 

Answer 2

With tabularray package the code for your table is simple and short:

\documentclass{article}
\usepackage[vietnamese]{babel}
\usepackage{tabularray}

\begin{document}

\noindent%2,
\begin{tblr}{hlines, vlines,
             colspec = {X[1, c,m] X[2,r,m] X[1,c,m]},
             rowsep  = 4pt,
             row{1}  = {font=\bfseries}
             }
Thời gian   & Công việc & {Người\\ thực hiện}   \\
\end{tblr}

\end{document}

Contents in cells you can simply split in two (or more) lines with {text \\ text}, for vertical center of them, you only needs to add option m to column specification. For more details of tabularray syntax see package documentation.