try it without xunicode and fontspec (you don't want those, xltxtra loads them automatically), thus:<div><br></div><div><div>\documentclass{article}</div><div><br></div><div>\usepackage{xltxtra}</div><div>\setmainfont[Mapping=tex-text]{Linux Libertine O}</div>
<div><br></div><div>\begin{document}</div><div><br></div><div>F\'{\i}thal</div><div><br></div><div>\emph{F\'{\i}thal}</div><div><br></div><div>\end{document}</div><div><br></div><div><br></div><div><br></div><div>
Rembrandt</div><div><br></div><div><br></div><div><br></div><br><div class="gmail_quote">On Sat, May 8, 2010 at 09:54, Chris Yocum <span dir="ltr"><<a href="mailto:cyocum@gmail.com">cyocum@gmail.com</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;">Hi Everyone,<br>
I was in the process of moving my thesis over from PDFTeX to<br>
XeTeX when I noticed a peculiar problem. When you have a dotless i in<br>
an emph command, it becomes un-italic. I am not sure if this is a<br>
Linux Libertine problem (the font that I am using) or a XeTeX problem<br>
so I thought that I would start here first. Below is a minimal<br>
example.<br>
<br>
Thanks in advance and for all the hard work on XeTeX,<br>
Chris<br>
<br>
\documentclass{article}<br>
<br>
\usepackage{xunicode}<br>
\usepackage{xltxtra}<br>
\usepackage{fontspec}<br>
\setmainfont[Mapping=tex-text]{Linux Libertine O}<br>
<br>
\begin{document}<br>
<br>
F\'{\i}thal<br>
<br>
\emph{F\'{\i}thal}<br>
<br>
\end{document}<br>
<br>
<br>
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</blockquote></div><br><br clear="all"><br>-- <br>人有不為也而後可以有為<br><br>
</div>