How to have nested list overlays without wobble

Question

I'm trying to use overlays to reveal successive bullet points in an itemize environment. Each item contains its own second-level itemize environment, which will also be revealed one item at a time.

What I would like to happen after advancing past the last item in any second-level itemize is for that second-level itemize to become invisible and take up no space, without causing any wobbling.

Here's what I have now:

\begin{frame}[t]
  \frametitle{Solutions to the Liar.}
  \begin{itemize}
    \item<2-> \textit{secundum quid et simpliciter}. \uncover<4->{\textbf{Solution.} Unclear.}
      \only<3>{\begin{itemize}
        \item Mentioned by Aristotle (\textit{Sophistici Elenchi}, 180b2-3).
      \end{itemize}}
    \item<5-> \textit{transcasus}. \uncover<9->{\textbf{Solution.} The Liar sentence is false.}
      \only<6-8>{\begin{itemize}
        \item<6-8> Derives from the Stoic \textit{metaptosis}: differing truth-values over time.
        \item<7-8> When I say ``I am speaking a falsehood'' I am referring to what I said immediately preceding to that sentence. 
        \item<8> If I didn't say anything before that, then the sentence is just false.
      \end{itemize}}
  \end{itemize}
\end{frame}

If you page through the frame, you can see that once each second-level itemize is shown, its parent item shifts upwards a small amount, and then shifts back down when the second-level itemize is hidden.

How can I get rid of this wobbling?

Answer 1

The problem is that the height of the second-level itemize environment is smaller than that of the second item in the first-level itemize environment. I was able to work around it this way:

\begin{frame}[t]
  \frametitle{Solutions to the Liar 2}
  \begin{itemize}
    \item<2-> \textit{secundum quid et simpliciter}. \uncover<4->{\textbf{Solution.} Unclear.}
      \begin{itemize}
        \item<only@3> Mentioned by Aristotle (\textit{Sophistici Elenchi}, 180b2-3).
      \end{itemize}
    \item<5-> \textit{transcasus}. \uncover<9->{\textbf{Solution.} The Liar sentence is false.}
      \begin{itemize}
        \item<6-8> Derives from the Stoic \textit{metaptosis}: differing truth-values over time.
        \item<7-8> When I say ``I am speaking a falsehood'' I am referring to what I said immediately preceding to that sentence. 
        \item<8> If I didn't say anything before that, then the sentence is just false.
      \end{itemize}
  \end{itemize}
\end{frame}