# Beamer shadows are different in pdfLateX and XeLaTeX

I am getting different results on the shadows beneath the boxes (title page and all others) depending on whether I compile with pfdLaTeX or XeLaTeX. When compiling with pdfLaTeX the shading works as expected, but when compiling with XeLaTeX there is no shading at all, just a solid black background.

My log file just gives me the following errors:

! Missing { inserted. - l.40 \end{frame} ! Missing { inserted. - l.40 \end{frame}

Overfull \hbox (299.25987pt too wide) detected at line 40 [] ! Missing } inserted. }

l.40 \end{frame} ! Missing } inserted. } l.40 \end{frame}

Package pgf Warning: Your graphic driver pgfsys-xetex.def does not support fadings. This warning is given only once on input line 40.

How should I go about fixing this? Here's my test MWE:

\documentclass{beamer}
\usetheme{Warsaw}
%\usetheme{Copenhagen}
\usepackage{ifxetex}

% LANGUAGE
\ifxetex
\usepackage{fontspec}
\usepackage{polyglossia}
\setmainlanguage{spanish}
\setotherlanguage{english}
\usepackage{xunicode}
\setsansfont[Mapping=tex-text]{Gill Sans MT}
\setmonofont[Mapping=tex-text,Scale=MatchLowercase]{Monaco}
\else
\usepackage[T1]{fontenc}
\usepackage[utf8]{inputenc}
\def\spanishoptions{mexico}
\usepackage[spanish]{babel}
\renewcommand{\contentsname}%
{Contenidos}}
\usepackage{lmodern}
\fi

\title[Short title]{Unusually long version of some generic title}
\subtitle{Important info, though not worthy of title status}
\author{A. U. Thor.}
\date{YYYY-MM-DD}
\institute[Short Institute]{Long form of the institutional name}

\begin{document}
\begin{frame}
\titlepage
\end{frame}

\section{Introduction}
\label{sec:introduction}

\begin{frame}
\frametitle{First slide}
Good stuff!
\end{frame}

\section{Body}
\label{sec:body}
\begin{frame}
\end{frame}

\end{document}

-
Which beamer version do you have? –  Joseph Wright Oct 19 '12 at 12:55
@JosephWright: beamer 2011/09/12 development version 3.18 A class for typesetting presentations (rcs-revision 70f9d8411e54) –  Ricardo Oct 19 '12 at 12:58
Try updating your beamer to the current release (3.22). –  Joseph Wright Oct 19 '12 at 13:04
tlmgr kindly requested that I upgrade to TeXLive 2012. I guess I should finally get around to it. I'll tell you how it goes in a few hours. –  Ricardo Oct 19 '12 at 13:21
You can just download beamer from CTAN, if you prefer. –  Joseph Wright Oct 19 '12 at 13:24

This is a 'known issue' with v3.18, which is fixed in v3.19 and later versions. Updating beamer should fix the problem.

-