I am observing strange behaviour in which toprule, midrule, bottomrule
fail to extend until the last columns of my table.
In the MWE below, I reproduce the issue using toprule,
& bottomrule
%%% Using MDPI journal template %%%
\begin{table}[!htbp]
\caption{My Table title} \label{tab1}
\begin{adjustwidth}{-\extralength}{0cm}
\centering
\begin{tabularx}{\textwidth}{@{} ll *{10}{c}}
\toprule
& & \multicolumn{2}{c}{Experiment 1} & \multicolumn{2}{c}{Experiment 2} & \multicolumn{2}{c}{Experiment 3} & \multicolumn{2}{c}{Experiment 4} & \multicolumn{2}{c}{Experiment 5} \\
\cmidrule(r{1ex}){3-4} \cmidrule(r{1ex}){5-6} \cmidrule(r{1ex}){7-8} \cmidrule(r{1ex}){9-10} \cmidrule(r{1ex}){11-12}
&& {ABC} & {XYZ} & {ABC} & {XYZ} & {ABC} & {XYZ} & {ABC} & {XYZ} & {ABC} & {XYZ} \\
%\midrule
\cmidrule{1-12} %\cmidrule(lr{1em}){1-12}
\multirow{ 3}{*}{Group 1}
& \textit{First Round} & 0.87 & 0.67 & 0.50 & 0.61 & 0.47 & 0.58 & 0.49 & 0.50 & 0.41 & 0.52 \\
& \textit{Second Round} & 0.87 & 0.67 & 0.50 & 0.61 & 0.47 & 0.58 & 0.49 & 0.50 & 0.41 & 0.52 \\
& \textit{Last Round} & 0.87 & 0.67 & 0.50 & 0.61 & 0.47 & 0.58 & 0.49 & 0.50 & 0.41 & 0.52 \\
\bottomrule
\end{tabularx}
\end{adjustwidth}
\end{table}
Output: