The onslide command is not working for me to uncover tables in columns. The command works fine outside of tabular, though. Also, it works on my desktop. I cannot figure out why it will not work on my laptop.
The following is an example. The onslide command works if I do not have \setbeamercovered{transparent} in the preamble, so that the columns are invisible. If I have \setbeamercovered{transparent} in the preamble, I get the desired 'grayed out' columns when I compile on my desktop, but the columns appear in all of the slides, with no graying out, when I compile on my laptop.
\begin{frame}
\frametitle{example}
\begin{tabular}{lc<{\onslide<2->}c<{\onslide<3->}c}
always & here & want & want\\
& & gray on & gray on \\
& & 1 only & 1 and 2\\
\end{tabular}
\end{frame}
