[XeTeX] Hyphenation around „ß“

[Georg Pfeiffer]

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Hi,

why does XeTeX (sometimes) suppress hyphenation round around an „ß“,
where TeX does not (minimal examples following)?

Georg


XeTeX:
- --8<---------------cut here---------------start------------->8---
\documentclass{article}
\usepackage[german]{babel}
\usepackage{xltxtra}
\begin{document}
\showhyphens{geißeln}
\showhyphens{wußte}
\end{document}
- --8<---------------cut here---------------end--------------->8---

- --8<---------------cut here---------------start------------->8---
This is XeTeX, Version 3.1415926-2.4-0.9998 (TeX Live 2012/Debian) (format=xelatex 2014.1.2)  8 JAN 2014 08:18
entering extended mode
 restricted \write18 enabled.
 %&-line parsing enabled.
**\input minxe.tex

…

*********************** \showhyphens: ***********************

Underfull \hbox (badness 10000) detected at line 5
 \EU1/lmr/m/n/10 geißeln
 []

*************************************************************


*********************** \showhyphens: ***********************

Underfull \hbox (badness 10000) detected at line 6
 \EU1/lmr/m/n/10 wußte
 []

*************************************************************

…

- --8<---------------cut here---------------end--------------->8---


PdfTeX:
- --8<---------------cut here---------------start------------->8---
\documentclass{article}
\usepackage[T1]{fontenc}
\usepackage[utf8]{inputenc}
\usepackage[german]{babel}
\begin{document}
\showhyphens{geißeln}
\showhyphens{wußte}
\end{document}
- --8<---------------cut here---------------end--------------->8---

- --8<---------------cut here---------------start------------->8---
This is pdfTeX, Version 3.1415926-2.4-1.40.13 (TeX Live 2012/Debian) (format=pdflatex 2014.1.2)  8 JAN 2014 08:20
entering extended mode
 restricted \write18 enabled.

…

Underfull \hbox (badness 10000) in paragraph at lines 6--6
[] \T1/cmr/m/n/10 gei-ßeln

Underfull \hbox (badness 10000) in paragraph at lines 7--7
[] \T1/cmr/m/n/10 wuß-te

…

- --8<---------------cut here---------------end--------------->8---
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