[Tex/LaTex] Change beamer itemize symbol and overlay

beameritemizeoverlays

For a beamer presentation and would like to change the color of an itemize symbol after a certain slide. Related questions were answered several times and the solution looks like:

The gray enviroment is defined in the preamble

 \newenvironment{grayenv}{\only{\setbeamercolor{local structure}{fg=gray!40}}}{}

and then used within the itemize enviroment:

\begin{itemize}
\item bla bla bla
\item<gray@2-> bla bla bla
\end{itemize}

The code will produce a slide where the bullet of the second item will change color from the 2nd slide onwards. I would also like the item points to appear later on in my slides. This is also a simple problem to solve:

\begin{itemize}
\item<1-2> bla bla bla
\item<3-> bla bla bla
\end{itemize}

with the first item being displayed on the first two slides, and the second one from the third onwards.

Now, I would like to define that one of the itemized points will be visible starting from slide x, and, later on, its color will be changed. Something like:

 \item<2-,gray@5->

Unfortunately, this command is not recognized, and I receive the following error:

Environment 2-,grayenv undefined

Also inverting the two elements, will not produce the desired result. Any suggestion?

Best wishes,
Leonardo

PS: here is a minal working example:

\documentclass[9pt,aspectratio=169]{beamer}

\colorlet{shadegray}{gray!40}
\newenvironment{grayenv}{\only{\setbeamercolor{local structure}{fg=gray!40}}}{}

\begin{document}

\begin{frame}
\begin{itemize}
\item<1-> Text
\item<2-> Text
\item<gray@3-> Text with changing bullet color
\item<4-> Bla bla
\end{itemize}
\end{frame}

\end{document}

I would like, that the third item, in addition to have its bullet color changed from the third slide onwards, will appear from the second one (with the standard bullet style).

Best Answer

Like this?

\documentclass[9pt,aspectratio=169]{beamer}

\colorlet{shadegray}{gray!40}
\newenvironment{grayenv}{\only{\setbeamercolor{local structure}{fg=gray!40}}}{}

\begin{document}

\begin{frame}
\begin{itemize}
\item<1-> Text
\item<2-> Text
\item<2-|gray@3-> Text with changing bullet color
\item<4-> Bla bla
\end{itemize}
\end{frame}

\end{document}