tabularray \cmidrule trim option not working

Question

I'm trying to use the trim option with tabularray, and I can't understand why it's not working. I read another thread about it which didn't help me. What am I doing wrong?

    \usepackage{tabularx}
    \usepackage{array}
    \usepackage{booktabs}
    \usepackage{tabularray}
    \UseTblrLibrary{booktabs}
        \begin{document}
        \begin{table}[t]
        \begin{tblr}{colspec={X[l] *{6}{X[c]}}}
            &\multicolumn{2}{c|}{multicol1} &\multicolumn{2}{c|}{multicol2} &\multicolumn{2}{c|}{multicol3}\\
          \cmidrule[r]{2-3} \cmidrule[lr]{4-5} \cmidrule[r]{6-7}
        \end{tblr}
        \caption{Caption}
        \end{table}
        \end{document}

This is the output I get:

Answer 1

Edit:

• Overleaf have so far installed old tabularray package version 2021L, which not support \cmidrule[r]{2-3} from your code fragment (see comment of @L.J.R., who is package author).
• Support for trim option (shortening) of \cmidrule is available with tabularray version 2021N and latter (see package author answer).
• Transcript of your code fragment to MWE (Minimal Working Example) with pure tabularray syntax is:

\documentclass{article}
\usepackage{tabularray}
\UseTblrLibrary{booktabs}
    
\begin{document}
\begin{table}[ht]
\begin{tblr}{colspec={X[l] *{6}{X[c]}}}
    & \SetCell[c=2]{c}  multicol1   &
        & \SetCell[c=2]{c}  multicol2   &
            & \SetCell[c=2]{c}  multicol3   &   \\
  \cmidrule[r]{2-3} \cmidrule[lr]{4-5} \cmidrule[r]{6-7}
1   & 2 & 3 & 4 & 5 & 6 & 7 \\      % <--- added row
\end{tblr}
\caption{Caption}
\end{table}
\end{document}

which gives after compilation with recent tabularray package version (2021Q) the following result:

This result you will get also with use of older version of the tabularray package, but not older as 2021N.