Displayed page breaks?

[Doug Wellington <ddw rincon com>]

Hi,

Brand new, so forgive me if I'm asking something silly.  I saw a discussion about this in the archives, but 
there didn't seem to be any resolution.

OK, I have opened a new diagram.  I'm a Merkan, so I have set the page size to "Letter" and I'm using 
landscape mode.  The paper size says 21.6cm x 27.9cm.  The margins say top: 13.47mm Bottom: 13.47mm 
Left:10.30mm Right: 10.30mm.  If I understand correctly, then the page breaks should be 21.6cm - 13.47mm - 
13.47mm (189.06mm) tall and 27.9cm - 10.30mm - 10.30mm (258.4mm) wide, right?  Then why are they displayed at 
~164mm tall and ~229mm wide according to the rulers?

Regards,
Doug