Groupbox calculate a wrong hight after the groupbox be hide then show

<zk>
	<panel title="panel" border="normal" width="100px"
		collapsible="true">
		<panelchildren>
			<groupbox mold="3d" height="100%">
				<caption label="Contacts" />
				<div>a</div>
				<div>a</div>
			</groupbox>
		</panelchildren>
	</panel>
	
	<borderlayout  width="100px">
		<west title="north" collapsible="true">
			<div>
				<groupbox mold="3d" height="100%">
					<caption label="Contacts" />
					<div>a</div>
					<div>a</div>
				</groupbox>
			</div>
		</west>
	</borderlayout>
</zk>