not render js object when zk object is hide

<zk>
<button label="load grid" id="btn" />
<div id="dv" fulfill="btn.onClick">
	<grid >
		<columns menupopup="auto">
			<column label="Author" />
			<column label="Title"/>
			<column label="Publisher"/>
			<column label="Hardcover"/>
		</columns>
		<rows>
			<row>
				<label value="Philip Hensher"/>
				<label value="The Northern Clemency"/>
				<label value="Knopf (October 30, 2008)"/>
				<label value="608 pages"/>
			</row>
			<row>
				<label value="Philip Hensher"/>
				<label value="The Fit"/>
				<label value="HarperPerennial (April 4, 2005)"/>
				<label value="240 pages"/>
			</row>
			<row>
				<label value="Philip Hensher"/>
				<label value="Kitchen Venom"/>
				<label value="Flamingo (May 19, 2003)"/>
				<label value="336 pages"/>
			</row>
			<row>
				<label value="Michael Greenberg"/>
				<label value="Hurry Down Sunshine"/>
				<label value="Other Press (September 9, 2008)"/>
				<label value="240 pages"/>
			</row>
			<row>
				<label value="Michael Greenberg"/>
				<label value="Painless Vocabulary (Painless)"/>
				<label value="Barron's Educational Series (September 1, 2001)"/>
				<label value="292 pages"/>
			</row>
			<row>
				<label value="Rick Perlstein"/>
				<label value="Nixonland: The Rise of a President and the Fracturing of America"/>
				<label value="Scribner; 1st Scribner Hardcover Ed edition (May 13, 2008)"/>
				<label value="896 pages"/>
			</row>
			<row>
				<label value="Rick Perlstein"/>
				<label value="Nixonland"/>
				<label value="Simon & Schuster (May 13, 2008)"/>
				<label value="0 pages"/>
			</row>
		</rows>
	</grid>
</div>
</zk>