Steps to Reproduce

<zk xmlns:w="http://www.zkoss.org/2005/zk/client">
	<hlayout vflex="1" hflex="1">
		<slider id="s1" maxpos="4" orient="vertical" slidingtext="Test"/>
		<slider id="s2" maxpos="4" slidingtext="Test"/>
	</hlayout>
	<button label="s1 vflex 1" onClick='s1.setHeight(null);s1.setVflex("1")'/>
	<button label="s2 hflex 1" onClick='s2.setWidth(null);s2.setHflex("1")'/>
</zk>

Current Result

1. Click the 1sy button, it does not update the 1st slider's height to vflex="1".
2. Click the 2nd button after step 1, the 1st slider's height's updated, but the 2nd slider's width does not resize to hflex="1", yet height changed to 200px.

Expected Result

Clicking the first button, the 1st slider should be resize to vflex="1" properly.
Clicking the 2nd button, the 2nd slider, the width should be resize to hflex="1", and the height shouldn't be resized to 200px.