I am attaching a sample page that should answer your questions - it includes a 100% by 100% RadScheduler in a page.
The overflow:hidden of the RadScheduler wrapper div is needed only under IE6, to make the adjustheight methods work when decreasing the height of the scheduler. The calls are needed under all browsers, because they set the height of the content area in pixels.
All the best,
the Telerik team
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