Beamer and ampersands (XeLaTeX)

Question

There are some known problems with ampersands and beamer (as discussed here, for instance), but I haven't been able to find a good reference...

Anyway, the concrete problem I have is with tables (also with amsmath environments): the ampersands break the uncover environments when compiling with XeLaTeX (but it works fine with PDFLaTeX). In the following example, I have:

• with PDFLaTeX both C and D and greyed out in the first slide
• with XeLaTeX, only C is greyed out in the first slide

In TikZ there is a workaround to avoid ampersands, but I don't see how to do with tables or amsmath environnemnts... Could it be a beamer bug?

\documentclass{beamer}
\beamertemplatetransparentcovered
\begin{document}
\begin{frame}
  \begin{tabular}{cc}
    A & B \\
    \pause
    C & D
  \end{tabular}
\end{frame}
\end{document}

Answer 1

If xetex does not like the &'s, than don't use them. https://tex.stackexchange.com/a/276133/36296 shows how to use other symbols as alignment markers for the table (maybe using a space is not the best idea, just change it to something that suits you).

\documentclass{beamer}
\beamertemplatetransparentcovered

\newenvironment{mytabular}[2][c]{%
    \catcode`\&=10
    \catcode`\ =4
    \begin{tabular}[#1]{#2}
    }{%
\end{tabular}
}

\begin{document}
    \begin{frame}
        \begin{tabular}{cc}
            A & B \pause \\
            C & D
        \end{tabular}
    \end{frame}

    \begin{frame}
        \begin{mytabular}{cc}
                    A B\\\pause
                    C D
        \end{mytabular}
    \end{frame}


\end{document}