color row in a table using cellcolor

Question

I'm trying to color the title line of the table by using the following code:

\documentclass[a4paper, 10pt]{article}

%% Packages %%
\usepackage[top=1in, bottom=1in, left=1in, right=1in]{geometry}
\usepackage{fancyhdr}
\usepackage{tikz,float}
\usetikzlibrary{shapes,arrows}
\usepackage{verbatim}
\usepackage{amsmath}
\usepackage{graphicx}
\usepackage{amssymb}
\usepackage{tabu}
\usepackage{sidecap}
\usepackage{multirow}
\usepackage[sorting=none]{biblatex}
\usepackage{subcaption}
\usepackage{setspace}
\usepackage{multicol}
\usepackage{scalerel}
\usepackage{enumitem}
\usepackage{empheq}
\usepackage{caption}
\usepackage{float}
\usepackage{kantlipsum}
\usepackage{xcolor,colortbl}
\usepackage{mathtools}
\usepackage{listings}
\usepackage[document]{ragged2e}
\setcounter{MaxMatrixCols}{20}
\definecolor{mygreen}{RGB}{28,172,0} % color values Red, Green, Blue
\definecolor{mylilas}{RGB}{170,55,241}
%% Title Page %%

\addbibresource{refbib.bib}

\begin{document}

\begin{table}[htbp]
\begin{center}
{\tabulinesep=1.2mm    
    \begin{tabu} to 0.9\linewidth { |[2pt] *{3}{X[1 c]|}[2pt] } \tabucline[2pt]{-}
        \multicolumn{3}{ |[2pt]c|[2pt] }{\cellcolor{green!20}Initial Conditions} \\ \tabucline[2pt]{-}
        $[x(0), y(0), z(0)]_{\text{R}}$ & [-29136.9, 0, 0] & m \\ \hline
        $[x(0), y(0), z(0)]_{\text{T}}$ & [0, 0, 0] & m \\ \hline    
        $[V_{x}(0), V_{y}(0), V_{z}(0)]_{\text{R}}$ & [680.7, 0, 680.7] & m/s \\ \hline
        $[V_{x}(0), V_{y}(0), V_{z}(0)]_{\text{Wind}}$ & [0, -10, 0] & m/s \\ \hline
        $[V_{x}(0), V_{y}(0), V_{z}(0)]_{\text{Wind Error}}$ & [0, 0, 0] & m/s \\ \hline
        Launch Angle & 45 & Deg \\ \tabucline[2pt]{-}
    \end{tabu}}
\end{center}
\caption{Initial conditions for test 1}
\end{table}
\end{document}

However, for some reason I still get this result:

Is there a reason that it doesn't show the line in green?

Thank you

Answer 1

I would not use the tabu package for my tables. IUnfortunately this package with attractive intentions is buggy (especially after new version of array` package on which it is based) and not maintained.

For your table seems to be more appropriate to use ordinary tabular environment, not lock cells' content in "prison of horizontal and vertical tables' rules, left align cells' n. For more vertical space I would use of the cellspace package:

\documentclass[a4paper, 10pt]{article}
\usepackage[top=1in, bottom=1in, left=1in, right=1in]{geometry}
\usepackage{mathtools}
\usepackage[skip=1ex]{caption}
\usepackage[table]{xcolor}
\definecolor{mygreen}{RGB}{28,172,0} % color values Red, Green, Blue
\definecolor{mylilas}{RGB}{170,55,241}
\usepackage{cellspace, makecell, tabularx}
\setlength\cellspacetoplimit{5pt}
\setlength\cellspacebottomlimit{5pt}


\begin{document}
    \begin{table}[htbp]
    \centering
\caption{Initial conditions for test 1}
\label{my table}
    \begin{tabular}{ *{2}{>{$}Sl<{$}} l } 
    \Xhline{1pt}
    \rowcolor{mygreen!20}
\multicolumn{3}{Sc}{Initial Conditions}     \\ 
    \Xhline{0.75pt}
{[x(0), y(0), z(0)]_{\mathrm{R}}}   
        & [-29136.9, 0, 0]      & m         \\  
{[x(0), y(0), z(0)]_{\text{T}}}     
        & [0, 0, 0]             & m         \\
{[V_{x}(0), V_{y}(0), V_{z}(0)]_{\text{R}}}
    & [680.7, 0, 680.7]         & m/s       \\ 
{[V_{x}(0), V_{y}(0), V_{z}(0)]_{\text{Wind}}}
    & [0, -10, 0]               & m/s       \\ 
{[V_{x}(0), V_{y}(0), V_{z}(0)]_{\text{Wind Error}}}
    &  [0, 0, 0]                & m/s       \\ 
\text{Launch Angle}             
    & 45                        & Degrees   \\ 
    \Xhline{1pt}
    \end{tabular}
    \end{table}
\end{document}

**Addendum:**The same table with use of the siunitx package. Use their names for units make their use more clear ... and hopefully encourage you to use it for all units in your document:

\documentclass[a4paper, 10pt]{article}
\usepackage[margin=1in]{geometry}
\usepackage[skip=1ex]{caption}
\usepackage[table]{xcolor}
\definecolor{mygreen}{RGB}{28,172,0} % color values Red, Green, Blue
\definecolor{mylilas}{RGB}{170,55,241}
\usepackage{cellspace, makecell, tabularx}
\setlength\cellspacetoplimit{5pt}
\setlength\cellspacebottomlimit{5pt}
\usepackage{siunitx}

\begin{document}
    \begin{table}[htbp]
    \centering
    \sisetup{per-mode=symbol}
\caption{Initial conditions for test 1}
\label{my table}
    \begin{tabular}{ *{2}{>{$}Cl<{$}} s } 
    \Xhline{1pt}
    \rowcolor{mygreen!20}
\multicolumn{3}{Cc}{Initial Conditions}             \\ 
    \Xhline{0.6pt}
{[x(0), y(0), z(0)]_{\mathrm{R}}}   
        & [-29136.9, 0, 0]      & \metre            \\  
{[x(0), y(0), z(0)]_{\text{T}}}     
        & [0, 0, 0]             & \metre            \\
{[V_{x}(0), V_{y}(0), V_{z}(0)]_{\text{R}}}
    & [680.7, 0, 680.7]         & \metre/\second    \\ 
{[V_{x}(0), V_{y}(0), V_{z}(0)]_{\text{Wind}}}
    & [0, -10, 0]               & \metre\per\second \\ 
{[V_{x}(0), V_{y}(0), V_{z}(0)]_{\text{Wind Error}}}
    &  [0, 0, 0]                & \metre\per\second \\ 
\text{Launch Angle}             
    & 45                        & Degrees   \\ 
    \Xhline{1pt}
    \end{tabular}
    \end{table}
\end{document}

Result is the same as it is at the first example.