Non aligned lines in tabular

Question

In this table, the two parts of the last line are not aligned. Why and how to fix it?

\documentclass{article}

\usepackage{amsfonts}
\usepackage{tabularx}
\usepackage[table]{xcolor}
\usepackage{wasysym}

\begin{document}

\begin{tabular}{@{} m{2cm} <{\hspace*{1mm}} | m{1.9cm} <{\hspace*{1mm}}}
\multicolumn{2}{c}{\cellcolor{black!20!white}{}}\\[-3mm]
\multicolumn{2}{c}{\cellcolor{black!20!white}{\footnotesize $\ \mathbf{15}$ \hspace{0pt plus 1filll} Test}}\\[1.5mm]
\scriptsize \hfill $\times \hspace{-1pt}\approx\hspace{-1pt}\checked$
& \scriptsize \hfill $\times \hspace{-1pt}\approx\hspace{-1pt}\checked$  \\                                                          
\dotfill\scriptsize $\square$\,$\square$\,$\square$ & \dotfill\scriptsize $\square$\,$\square$\,$\square$\\
\dotfill\scriptsize $\square$\,$\square$\,$\square$ & \dotfill\scriptsize $\square$\,$\square$\,$\square$\\
\dotfill\scriptsize $\square$\,$\square$\,$\square$ & \dotfill\scriptsize $\square$\,$\square$\,$\square$\\[3mm]
\end{tabular}

\end{document}

Log

This is pdfTeX, Version 3.14159265-2.6-1.40.18 (TeX Live 2017) (preloaded format=pdflatex) \write18 enabled. entering extended mode (./bac_a_sable.tex LaTeX2e <2017-04-15> Babel <3.10> and hyphenation patterns for 84 language(s) loaded. (/usr/local/texlive/2017/texmf-dist/tex/latex/base/article.cls Document Class: article 2014/09/29 v1.4h Standard LaTeX document class (/usr/local/texlive/2017/texmf-dist/tex/latex/base/size10.clo)) (/usr/local/texlive/2017/texmf-dist/tex/latex/amsfonts/amsfonts.sty) (/usr/local/texlive/2017/texmf-dist/tex/latex/tools/tabularx.sty (/usr/local/texlive/2017/texmf-dist/tex/latex/tools/array.sty)) (/usr/local/texlive/2017/texmf-dist/tex/latex/xcolor/xcolor.sty (/usr/local/texlive/2017/texmf-dist/tex/latex/graphics-cfg/color.cfg) (/usr/local/texlive/2017/texmf-dist/tex/latex/graphics-def/pdftex.def (/usr/local/texlive/2017/texmf-dist/tex/generic/oberdiek/infwarerr.sty) (/usr/local/texlive/2017/texmf-dist/tex/generic/oberdiek/ltxcmds.sty)) (/usr/local/texlive/2017/texmf-dist/tex/latex/colortbl/colortbl.sty)) (/usr/local/texlive/2017/texmf-dist/tex/latex/wasysym/wasysym.sty) (./bac_a_sable.aux) (/usr/local/texlive/2017/texmf-dist/tex/context/base/mkii/supp-pdf.mkii [Loading MPS to PDF converter (version 2006.09.02).] ) (/usr/local/texlive/2017/texmf-dist/tex/latex/amsfonts/umsa.fd) (/usr/local/texlive/2017/texmf-dist/tex/latex/amsfonts/umsb.fd) (/usr/local/texlive/2017/texmf-dist/tex/latex/wasysym/uwasy.fd) [1{/usr/local/t exlive/2017/texmf-var/fonts/map/pdftex/updmap/pdftex.map}] (./bac_a_sable.aux) )< /usr/local/texlive/2017/texmf-dist/fonts/type1/public/amsfonts/cm/cmr10.pfb> Output written on bac_a_sable.pdf (1 page, 42174 bytes). SyncTeX written on bac_a_sable.synctex.gz. Transcript written on bac_a_sable.log.

Answer 1

The interaction between m columns and the \\[..] optional length argument was corrected in the 2018 array package release so with an up to date system you get better alignment. In general though using m especially in combination with <{\hspace*{1mm} is a rather fragile setting. (m columns are designed for multi-line paragraph boxes with line breaking within the cell, you do not have that here, and adding an \hspace just on the last line of a paragraph only does anything sensible as there is only one line here.