Default Top-Bottom widgets

In all those fancy screenshots of Zooper widgets, how do they get the widget to fill the entire screen, top to bottom, left to right? Thanks!

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My devices:
Nexus 10 - Android 4.4.2 Stock Rooted // franco.Kernel r15
Nook Tablet - CM10.1

Check out my Zooper Widgets @ http://forum.xda-developers.com/show....php?t=2588966