\overprint inside \itemize problem — shaky frames

Question

I'm having troubles with a presentation. I want to create something like this

\documentclass{beamer}
\usepackage{ulem} % To strikeout text

\begin{document}
\begin{frame}
\begin{itemize}
\onslide<1->{
\item item 1
\item item 2
\item item 3}
\begin{overprint}
\onslide*<2>{\item item 4}
\onslide<3>{\item \sout{item 4} $\to$ Actually we'll going to put here another item: item 5}
\end{overprint}
\end{itemize}
\end{frame}
\end{document}

but the frames move up and down in a strange way. Can you please help me to make the frames stay fixed?

Answer 1

You can make \sout overlay specification aware like this:

\documentclass{beamer}
\usepackage{ulem} % To strikeout text
\renewcommand<>{\sout}[1]{\alt#2{\beameroriginal{\sout}{#1}}{#1}}
\begin{document}
\begin{frame}
\begin{itemize}
\item<1-> item 1
\item<1-> item 2
\item<1-> item 3
\item<2-> \sout<3>{item 4} \visible<3>{$\to$ Actually we'll going to put here another item: item 5}
\end{itemize}
\end{frame}
\end{document}

Line 3 redefines \sout so that \sout<spec>{text} expands to \alt<spec>{text}{\sout{text}}. Then you need \visible instead of \only to make sure that the space taken up by the revealed text is reserved even when it's not revealed.

With incremental specifications you can write:

\begin{frame}
\begin{itemize}
\item<+-> item 1
\item<.-> item 2
\item<.-> item 3
\item<+-> \sout<+>{item 4} \visible<.>{$\to$ Actually we'll going to put here another item: item 5}
\end{itemize}
\end{frame}