Beamer: effect of newline and hphantom

Question

Why is it that the file

\documentclass{beamer}
\begin{document}
  \begin{frame}
    a\\
    \hphantom{ }b
  \end{frame}
\end{document}

produces an a and a b vertically aligned with a line skip in between whereas the same file with \\ replaced by \newline produces the expected: an a, then a b on the next line, indented by one space?

Is that a bug in Beamer (in documentclass Article, both versions have the same, expected effect)?

Thanks!

Answer 1

I'd call this a feature of how beamer redefines \\. After it TeX is in vertical mode, so the \hphantom, which ultimately does \box2 doesn't start horizontal mode.

Use

\leavevmode\hphantom{ }

Note that standard LaTeX doesn't start vertical mode after \\.