Currently Being ModeratedOct 20, 2011 9:11 AM (in response to dgbmunger)
You must first set the Document Margins in the Document Inspector, Document Tab, Document Margins area. This setting is the narrowest margin that you intend to use anywhere in the document.
Then when you add a Layout Break, go to the Layout Inspector, Layout Tab, Layout Margins area and add more margin width with the settings there.
The Document Margins dictate the maximum text width (smallest margins) anywhere in the document. The Layout Margins further narrow the text area on a per-layout-region basis.