In docbook-xsl-ns-1.76.1 with saxon, webhelp.xsl ignores the titleabbrev element.
For example, this generates "Long title" in the TOC:
<article xmlns="http://docbook.org/ns/docbook" version="5.0" xml:id="home">
<title>Long title</title>
<titleabbrev>Abbrev</titleabbrev>
Possible cause:
In <xsl:template match="d:book|d:part..." mode="webhelptoc"> (on line 660), this change seems to fix the problem:
- <xsl:apply-templates select="." mode="title.markup"/>
+ <xsl:apply-templates select="." mode="titleabbrev.markup"/>
FWIW in autotoc.xsl, <xsl:template name="toc.line"> calls titleabbrev.markup mode, instead of title.markup, in a similar context.
A fix for this issue has been added to the current codebase.
Please test the fix with the latest snapshot from:
http://docbook.sourceforge.net/snapshots/