... specified by the selection attribute.
For its expected behavior, see the section <maction> in MathML 1.01:
<http://www.w3.org/TR/REC-MathML/chap3_6.html#sec3.6.1>

Change-Id: I70c1b2cfe1afec730f3e67ba0938bbaf8ada8e23
Reviewed-on: https://gerrit.libreoffice.org/14600Reviewed-by: Caolán McNamara <caolanm@redhat.com>
Tested-by: Caolán McNamara <caolanm@redhat.com>