[XeTeX] Minion Pro + memoir

[Musa Furber]

The following LaTeX file uses Minion Pro and memoir. When I set the  
typeblock width to anything less than 104mm, some of Minion's  
characters show up as x-blocks. The same does not happen with Adobe  
Garamond Pro.

Anyone have any ideas what's going on?

%&program=xelatex

\documentclass[12pt,a4paper,article]{memoir}

%%%
% Set up the typeblock for the page. Anything less than 104mm causes  
problems.
% It seems to happen only with paragraphs that are not indented at all.
%
\settypeblocksize{164mm}{95mm}{*} % what I want, but broken
%\settypeblocksize{164mm}{103mm}{*} % still broken
%\settypeblocksize{164mm}{104mm}{*} % this works

\checkandfixthelayout

\usepackage{fontspec}
\defaultfontfeatures{%
	Numbers=OldStyle,
	Mapping=tex-text
	}
\setromanfont{Minion Pro}

%%%
% Code for faking characters with underdots; it's necessary for  
transliterating
% Arabic and other languages.
%
\def\diatop[#1|#2]{{\leavevmode\setbox1=\hbox{{#1{}}}\setbox2=\hbox{{#2{ 
}}}%
  \dimen0=\ifdim\wd1>\wd2\wd1\else\wd2\fi%
  \dimen1=\ht2\advance\dimen1by-1ex%
  \setbox1=\hbox to1\dimen0{\hss#1\hss}%
  \rlap{\raise1\dimen1\box1}%
  \hbox to1\dimen0{\hss#2\hss}}}

\def\d#1{\smash{\diatop[\raise-.55em\hbox{\hskip0.125em.}|#1]}}
%
%
% Even though I removed all of the underdot characters from the example,
% commenting out the following macro makes things look better, even at  
95mm
%
\expandafter\def\csname U\string\=\endcsname#1{#1^^^^0304} % also  
changes things
%
% When the above is commented out, the first line of the first paragraph
% extends beyond the right margin without any x-boxes showing up.  
Otherwise,
% the x-boxes show up.
%
%%%

\begin{document}

\chapter{It's all the same text}

Ahmad ibn al-Husayn ibn Admad al-Asfah\=an\=i,
Ab\=u Shuj\=a`, was born in 433 AH. He studied Sh\=afi`\=i fiqh in  
Basra for forty years. He was appointed judge of Asfah\=an, Persia, in  
447 AH. During his appointment

Ahmad ibn al-Husayn ibn Admad al-Asfah\=an\=i, Ab\=u Shuj\=a`, was born  
in 433 AH. He studied Sh\=afi`\=i fiqh in Basra for forty years. He was  
appointed judge of Asfah\=an, Persia, in 447 AH. During his

Ahmad ibn al-Husayn ibn Admad al-Asfah\=an\=i, Ab\=u Shuj\=a`, was born  
in 433 AH. He studied Sh\=afi`\=i fiqh in Basra for forty years. He was  
appointed judge of Asfah\=an, Persia, in 447 AH. During his appointmen

\chapter{Now, without any paragraph indents ever}

\parindent=0pt
\parskip=0.5cm
Ahmad ibn al-Husayn ibn Admad al-Asfah\=an\=i, Ab\=u Shuj\=a`, was born  
in 433 AH. He studied Sh\=afi`\=i fiqh in Basra for forty years. He was  
appointed judge of Asfah\=an, Persia, in 447 AH. During his appointmen

Ahmad ibn al-Husayn ibn Admad al-Asfah\=an\=i, Ab\=u Shuj\=a`, was born  
in 433 AH. He studied Sh\=afi`\=i fiqh in Basra for forty years. He was  
appointed judge of Asfah\=an, Persia, in 447 AH. During his appointmen

\end{document}