How can I prevent footnotes in beamer from inserting a blank slide?

Question

When a footnote is created in beamer that contains a box whose depth is too great, beamer inserts a blank slide before the slide with the footnote.

MWE

\documentclass{beamer}
\setbox0=\hbox{}
\dp0=1.131ex
\begin{document}
\begin{frame}
\footnote{\box0 }
\end{frame}
\end{document}

If I change the 1.131ex to 1.130ex, there is only one slide.

My actual problem doesn't involve an empty box with an artificial depth (of course). I can work around this issue by putting the material with the too-great depth into a box and set its \dp to 0pt, but this seems like the wrong solution in general.

What is the correct method to prevent an extra slide from being inserted in this case?

Interestingly, one my TeXLive2017 installation I always get one page, even if I increase 1.31ex like crazy. — , Feb 06 '18 at 19:46
Which tex distribution do you have and which engine are you using? — samcarter_is_at_topanswers.xyz, Feb 06 '18 at 20:10
@samcarter Sure. sharelatex exhibits the same behavior if you want to play around with it. — TH., Feb 06 '18 at 20:28
@samcarter The log is too large to include in the question. I put it on pastebin https://pastebin.com/g5h2jnpq — TH., Feb 06 '18 at 20:31
@TH. Thanks for the log. The problem is your beamer version. I am able to reproduce the problem with the version you use, but it works fine with the current version. Can you update to the current version? — samcarter_is_at_topanswers.xyz, Feb 06 '18 at 20:38

samcarter_is_at_topanswers.xyz · Accepted Answer · 2023-08-31T10:20:07.113

This briefly worked in beamer v3.55, which can be checked out from https://github.com/josephwright/beamer/releases/tag/v3.55

Workaround for beamer v3.54 or older:

\documentclass{beamer}
\setbox0=\hbox{}
\dp0=1.131ex
\makeatletter
\long\def\beamer@doseveralframes#1{%
  \ifx\beamer@againname@empty\else%
    % Again stuff
    \expandafter \gdef\csname beamer@again@\beamer@againname\endcsname{{#1}}%
  \fi%
  \beamer@slideinframe=1\relax%
  \loop%
  \beamer@anotherslidefalse%
  \gdef\beamer@doifnotinframe{}%
  \def\beamer@doifinframe{\begin{beamer@frameslide}%
    #1%
  \end{beamer@frameslide}}%
  \beamer@masterdecode{\beamer@whichframes}%
  \beamer@donow%
  \ifbeamer@twoscreenstext%
    \beamer@dosecondscreennow{#1}% two screen stuff
  \fi%
  \ifbeamer@anotherslide
  \advance\beamer@slideinframe by 1\relax
  \repeat%
  \beamer@writeslidentry%
  \beamer@reseteecodes}
\makeatother
\begin{document}
\begin{frame}
\footnote{\box0 }
\end{frame}
\end{document}

Workaround for beamer v3.56 or newer:

\documentclass{beamer}
\setbox0=\hbox{}
\dp0=1.131ex
\makeatletter
% The main decoding macro tolerates a range of active characters, which
% require a little set up. In particular, as an active space is allowed
% all of the lines here have to be terminated with "%". The two-step
% setup for \beamer@@@temp makes sure everything is expanded and removes
% all of the spaces at this stage.
\newbox\beamer@decode@box
\begingroup
  \catcode\|=\active \catcode:=\active
  \catcode\,=\active \catcode.=\active
  \catcode\+=\active \catcode-=\active
  \catcode\(=\active \catcode)=\active
  \catcode\ =\active \xdef\beamer@masterdecode#1{% \noexpand\beamer@localanotherslidefalse% \setbox0=\hbox{% \unexpanded{% \ifnum\catcode|=\active\edef|{\string|}\fi%
\ifnum\catcode\:=\active\edef:{\string:}\fi% \ifnum\catcode,=\active\edef,{\string,}\fi%
\ifnum\catcode\.=\active\edef.{\string.}\fi% \ifnum\catcode+=\active\edef+{\string+}\fi%
\ifnum\catcode\-=\active\edef-{\string-}\fi% \ifnum\catcode(=\active\edef({\string(}\fi%
\ifnum\catcode\)=\active\edef){\string)}\fi% \ifnum\catcode\ =\active\edef {\string }\fi}%
\edef\noexpand\beamer@@@temp{#1\string|stop\string:0\string|}%
\edef\noexpand\beamer@@@temp{\unexpanded{\expandafter\zap@space\beamer@@@temp}%
\space\noexpand@empty}%
\unexpanded{\expandafter\beamer@decode\beamer@@@temp%
\ifbeamer@localanotherslide\aftergroup\beamer@localanotherslidetrue\fi}%
}%
}%
\endgroup
\makeatother
\begin{document}
\begin{frame}
\footnote{\box0 }
\end{frame}
\end{document}

Still having this problem on TeXLive 2020. Fix didn't work neither. — BadAtLaTeX, Aug 30 '23 at 23:28
mmm, looks like this came back sometime between TL2018 and 2019 — samcarter_is_at_topanswers.xyz, Aug 31 '23 at 09:59
it worked prior to https://github.com/josephwright/beamer/commit/523de6fd97b83d2c26a247b94e0fad6302e4ca41 — samcarter_is_at_topanswers.xyz, Aug 31 '23 at 10:09
If it matters, my MWE is slightly different. I am using this \begin{tikzpicture}[remember picture,overlay] \node at (current page.north east){% \footnotetext{abc}; \end{tikzpicture} to keep a fixed footnote position. From the .log pdfTeX, Version 3.14159265-2.6-1.40.21 (TeX Live 2020/Debian) [...] beamer.cls 2020/07/22 v3.59 which might not be the newest, but is a container. — BadAtLaTeX, Aug 31 '23 at 10:14
@BadAtLaTeXProgramming The wonders of using git for version control :) — samcarter_is_at_topanswers.xyz, Aug 31 '23 at 10:17
@BadAtLaTeXProgramming I added a new workaround. I'm not sure what the actual problem is you are trying to solve, but it looks like an xy problem. Maybe you could ask a question about your actual problem? — samcarter_is_at_topanswers.xyz, Aug 31 '23 at 10:24
I did. See here. It turned out to be caused by inline math in the aforementioned footnote. — BadAtLaTeX, Aug 31 '23 at 15:51

How can I prevent footnotes in beamer from inserting a blank slide?

1 Answers1

Workaround for beamer v3.54 or older:

Workaround for beamer v3.56 or newer: