[XeTeX] \textsuperscript and polyglossia

[kilian at nihilnovi.de]

Hello,

the failure comes when I do a \usepackage{xltxtra} in the header.
Afterwards \textsuperscript{} is broken in greek mode. So the following is
broken:

\documentclass[12pt,a4paper]{article}
\usepackage{bidi}
\usepackage{polyglossia}
\usepackage{fontspec}
\usepackage{xltxtra,xunicode}
\setdefaultlanguage{english}
\setotherlanguage[variant=ancient,attic=true]{greek}
\newfontfamily\greekfont{SBL Greek}
\begin{document}

\begin{greek}
123\textsuperscript{1}
\end{greek}
Text here...
\end{document}