The easiest way to do this is to edit the default HeaderStyle of the RadTileViewItems and add an animation which collapses the header in the Maximized visual state.
I've attached a sample project which shows how you can do this so could you please examine it and see if this is what you're looking for?
Keep in mind that if you hide the header of the maximized item you won't be able to restore it, because the Maximize/Restore button is in the header.
If you have more questions feel free to ask.
the Telerik team
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