srcFail.zul

<?page title="Home"?>
<zk>
<window border="0" id="mainWindow" style="overflow:auto" width="100%" height="100%" >
	
	<borderlayout>
		<north border="1">
			
		</north>
		
		<center border="none" flex="true" autoscroll="true">			
			<include id="mainBody" src="/test/srcFail.zul"/>
		</center>
		
		<!--  <south border="none">
			<include src="">
		</south>-->
	</borderlayout>
</window>
</zk>

new_file.zul

<?xml version="1.0" encoding="UTF-8"?>
<zk xmlns="http://www.zkoss.org/2005/zul">
    <window id="info">
 
        
        <button label="Button Back" onClick="append()">
<attribute name="onClick"><![CDATA[

mainBody.setSrc("srcFail.zul"); //NPE Include donīt exist

]]></attribute>
</button>
    </window>
</zk>

srcFail.zul

<zk>
<window >
<button label="New page" onClick="append()">
<attribute name="onClick"><![CDATA[

mainBody.setSrc("new_file.zul?aa=bb");
//include.setSrc("new_file.zul"); without param, works fine
]]></attribute>
</button>


</window>
</zk>