2.1.1494 Part 1 Section 21.2.2.104, manualLayout (Manual Layout)

a.   The standard does not place any restrictions on when the attributes can be specified.

Office requires that attributes h, w, x, and y all be specified if one is specified and the ancestors include legend or plotArea.  If x or y are specified and the ancestors include dispUnitsLbl, dLbl, title, or trendlineLbl, both shall be specified.