Max number of nested \input in LaTeX/Beamer

When using the beamer documentclass, it looks like the third level of nested input is ignored:

\documentclass{beamer}
\input{body}

body.tex:
\begin{document}
\input{file1}
\input{file2}
\end{document}

file2.tex:
\input{file21}

The content of file21.tex is ignored with documentclass beamer, but correctly inserted if I use a documentclass article, for example.

Has anyon开发者_开发技巧e seen something like this?

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Do you perhaps use the [ignorenonframetext] option ? If so, \input is taken as nonframe text and ignored.

You can do \mode<all>{\input{file}} to force the input to work in the presentation mode. You will need to start the included file with \mode* to start ignoring non frame text again.