Set the other columns as explicitly using the default font, to work around the previous issue (but still pack columns, for consistency).
<?xml version="1.0" encoding="UTF-8"?>
<?eclipse version="3.2"?>
<plugin>
<extension
point="org.eclipse.help.toc">
<toc
file="sdkTOC.xml"
primary="true"/>
<toc
file="tocStart.xml"
primary="false"/>
<toc
file="tocReference.xml"
primary="false"/>
<toc
file="tocTasks.xml"
primary="false"/>
<toc
file="toccuscomp.xml"
primary="false"/>
<index path="index" />
</extension>
</plugin>