The default value of this property is false, which indicates the traditional behavior with coordinates relative to page edges. If set to true, coordinates are considered relative to page margins.
For instance, if this property is false (default), all page margins are 1 in, and a top-level object's X coordinate is specified as ".5in", the object would be located 0.5in from the left edge of the page - i.e. in the middle of the left page margin.
If this property is set to true, the same object would be located 0.5in to the right of the left page margin - 1.5in from the left edge of the page.