2.1.1217 Part 1 Section 20.1.2.2.37, style (Shape Style)

a.   The standard states that the fontRef attribute applies to parent elements pic, cxnSp and sp.

In Office, the fontRef attribute is not used for parent elements pic and cxnSp.

b.   The standard allows a sp, pic or cxnSp element to have similar formatting options defined in both the style and spPr elements.

In Office, shape properties (spPr) defined on the parent element will override similar style components (lnRef, effectRef, fillRef, fontRef) defined for this element.

c.   The standard allows similar text formatting properties to be defined for parent element sp by style or txBody.

In Office, child elements from txBody for parent element sp will override similar style properties defined in the fontRef child element in this element.