2.1.1806 Part 4 Section 7.1.2.15, brk (Break)

a.   The standard states that the only attribute on the brk element is alnAt.

If the brk element is used on a box element, Word ignores the alnAt attribute and instead reads and writes the val attribute with the same meaning as alnAt.

This note applies to the following products: 2007, 2007 SP1.

b.   The standard does not specified default behavior when alnAt is omitted.

If alnAt attribute is omitted, Word aligns with the start of the first line of the equation.

This note applies to the following products: 2007, 2007 SP1, 2007 SP2.

c.   The standard allows any value for alnAt between 1 and 255.

Word requires the value of alnAt to be less than the index of the first operator in the equation with a manual break.

d.   The standard allows brk element to be specified for any math run.

Word ignores brk if it is specified for a  math run which does not begin with an operator.

e.   The standard says the alignAt attribute specifies how to align the current line of the equation with the previous line of the equation.

In Word, the alignAt attribute specifies how to align the current line of the equation with the first line of the equation.

f.   The standard states that the only attribute on the brk element is the alnAt attribute.

If the brk element is used on a box element, Word writes a val attribute with the same meaning as the alnAt attribute. The alnAt attribute, if present, is read correctly.

This note applies to the following products: 2007 SP2.