# + overlay specification broken?

Since a recent update, the +- overlay specification doesn't seem to work anymore, for environments at least. I'm up to date with TexLive 2015 (beamer 36461 (3.36)). Consider the following MWE:

\documentclass{beamer}

\begin{document}
\begin{frame}
\begin{block}{On the first slide}
Hello
\end{block}
\begin{block}<only@+>{On the second slide}
Goodbye
\end{block}
\end{frame}

\end{document}

I expect the second block to appear on the second slide (that's what it used to do until recently) but the two blocks are on the same slide.

• Your example doesn't use <+->. – cfr Nov 22 '15 at 14:26
• @samcarter that would defeat the whole purpose of the + overlay specification – wilk Nov 22 '15 at 14:29
• I get the same result with TL 2014. – cfr Nov 22 '15 at 14:30
• @wilk sorry, I was confused because before the edit there had not been any overlay specs in the MWE. I will delete my comment – samcarter_is_at_topanswers.xyz Nov 22 '15 at 14:32
• <+(1)-> does work but <+-> does not. Overlay specifications are tricky.... I don't see the point of trying to put only@ in there. – cfr Nov 22 '15 at 14:34

The behaviour is the intended behaviour as documented in the manual (90):

\begin{itemize}
\item<+-> Apple
\item<+-> Peach
\item<+-> Plum
\item<+-> Orange
\end{itemize}

The effect of the +-sign is the following: You can use it in any overlay specification at any point where you would usually use a number. If a +-sign is encountered, it is replaced by the current value of the LaTeX counter beamerpauses, which is 1 at the beginning of the frame. Then the counter is increased by 1, though it is only increased once for every overlay specification, even if the specification contains multiple +-signs (they are replaced by the same number). In the above example, the first specification is replaced by <1->. Then the second is replaced by <2-> and so forth.

• Also note this is unaltered between 2014 and 2014 :-) – Joseph Wright Nov 22 '15 at 14:57
• @JosephWright Indeed, it is not even altered between 2014 and 2015, either. – cfr Nov 22 '15 at 16:08