Mixing overprint with blocks of enumerations

Question

I'd like to overlay a series of different blocks, each of which includes an enumeration that pauses with each item. The overprint environment handles this pretty well, but it doesn't seem to be mixing with the theme I'd like to use: Warsaw. Here's a minimal example of my problem:

\documentclass{beamer}

\usetheme{Warsaw}

\begin{document}

\begin{frame}{Test}
  \begin{center}
  text before
  \pause
  \begin{overprint}%
    \onslide<2-3>\begin{center}{
        \begin{block}{Some title here}
        \begin{enumerate}[<+->]
        \item One
        \item Two
        \end{enumerate}
        \end{block}
    }\end{center}
    \onslide<4->\begin{center}{
        \begin{block}{Some title here}
        \begin{enumerate}[<+->]
        \item CHicken
        \item Duck
        \item Rooster
        \end{enumerate}
        \end{block}
    }\end{center}
  \end{overprint}
  text after
  \end{center}
\end{frame}

\end{document}

The blocks are overlayed ontop of each other nicely but the bullet points that get generated go haywire. Here's a screen shot of what happens by the last slide:

Things work fine if I don't include the pauses between each enumeration item. Things also work well if I don't use the Warsaw theme.

Any thoughts as to why the Warsaw theme is corrupting my enumerations?

Answer 1

It's not just Warsaw; using CambridgeUS, for example, the problem also appears. Removing the inner center environments (which in your concrete example have no real effect) or using \centering instead solves the problem:

\documentclass{beamer}
\usetheme{Warsaw}

\begin{document}

\begin{frame}{Test}
  \begin{center}
  text before
  \pause
  \begin{overprint}%
    \onslide<2-3>{%
        \centering
        \begin{block}{Some title here}
        \begin{enumerate}[<+->]
        \item One
        \item Two
        \end{enumerate}
        \end{block}\par}
    \onslide<4->{%
        \centering
        \begin{block}{Some title here}
        \begin{enumerate}[<+->]
        \item CHicken
        \item Duck
        \item Rooster
        \end{enumerate}
        \end{block}\par}
  \end{overprint}
  text after
  \end{center}
\end{frame}

\end{document}

An image of the last slide:

I am not sure if perhaps the effect that you are trying to achieve is this one (using overlayarea instead of overprint):

\documentclass{beamer}
\usetheme{Warsaw}

\begin{document}

\begin{frame}{Test}
  \begin{center}
  text before
  \pause
  \begin{overlayarea}{\textwidth}{3.3cm}
    \only<2-3>{%
        \begin{block}{Some title here}
        \begin{enumerate}[<+->]
        \item One
        \item Two
        \end{enumerate}
        \end{block}}
    \only<4-7>{%
        \begin{block}{Some title here}
        \begin{enumerate}[<+(2)->]
        \item CHicken
        \item Duck
        \item Rooster
        \end{enumerate}
        \end{block}}
  \end{overlayarea}
  text after
  \end{center}
\end{frame}

\end{document}

The last slide:

By the way, you were using \onslide<2-3>\begin{center}{...}\end{center} and the proper syntax would be \onslide<2-3>{\begin{center}...\end{center}}; this, however doesn't solve the problem in this case; one possible solution is the one I described above.