Comment 2 for bug 1302627

Addendum:
1) The actual screen size for above example is: 1280 x 800
2) Dock has 'Hiding' turned on (maximized windows extend to the bottom of the screen) [*]

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[*] whether or not the Dock has 'Hiding' turned on makes no difference. If turned off, the recorded window height is reduced by the height of the Dock (with both backends equally), and the "maximized" window does not extend beyond the upper edge of the Dock.