[texhax] Beamer bug with "cases"-environment in amsmath

[Ozan Öktem]

Hi,

It seems that there is a bug in Beamer that prevents the usage of  
"\alert<n>" command within the "cases"-environment in the amsmath  
package. This causes a Beamer/LaTeX-complie error whereas the   
corresponding "\alert"command without slidenumber specification works  
fine.

Any ideas for a workaround?

Beamer version: Version 3.06 (TeXLive CD 2007)

Below is a minimal example together with an excerpt from log-file.  
The first "cases"-environment doesn't work whereas the next works fine.

------------ start ------------
\documentclass{beamer}
\usepackage{amsmath}

\begin{document}

\begin{frame}

\[
\begin{cases}
   \alert<1>{x} &
\end{cases}
\]

\[
\begin{cases}
   \alert{x} &
\end{cases}
\]

\end{frame}

\end{document}
------------ end ------------

------------ excerpt from log-file ------------
! Argument of \beamer at next has an extra }.
<inserted text>
                 \par
l.22 \end{frame}

?
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