Avoid flickering text when expanding a point in a list

Question

I would like to typeset a list in a beamer presentation, where each point in the list is expanded and then reduced again on subsequent slides. However, I want all the points below the currently expanded point to move downwards and upwards again - instead of having a reserved space, where the expansion fits into.

The following example basically does what I would like to achieve, but point 1 in the list flickers when it is expanded and reduced, because it spans over two lines - despite the overlayarea environment:

\documentclass{beamer}
\begin{document}
\begin{frame}{Example}
These are my points:
\begin{overlayarea}{\textwidth}{\textheight}
\begin{itemize}
    \item<1-3> Point 1, which spans\\over two rows
        \only<2>{
            \begin{itemize}
                \item Point 1a
                \item Point 1b
            \end{itemize}
        }
    \item<1-3> Point 2
\end{itemize}
\end{overlayarea}
\end{frame}
\end{document}

Is there any way to avoid this? Thank you very much for your help!

Answer 1

You can use another overlayarea environment for the inner list:

\documentclass{beamer}
\begin{document}
\begin{frame}{Example}
These are my points:

\begin{overlayarea}{\textwidth}{.8\textheight}
\begin{itemize}
    \item<1-3> Point 1, which spans\par over two rows
        \only<2>{
        \begin{overlayarea}{\linewidth}{1.6cm}
            \begin{itemize}
                \item Point 1a
                \item Point 1b
            \end{itemize}
        \end{overlayarea}
        }
    \item<1-3> Point 2
\end{itemize}
\end{overlayarea}

\end{frame}
\end{document}

The result: