Steps to Reproduce

    <library-property>
        <name>org.zkoss.zul.nativebar</name>
        <value>false</value>
    </library-property>

Cannot use anymore neither sizedByContent="true" in Listbox/Grid nor hflex="min" in listheader.

Please check this simple zul.

<window title="Listbox">
	<listbox  checkmark="false" multiple="false" style="border:none"  sizedByContent="true">
		<listhead>
			<listheader label="Client"  />
			<listheader label="Description" />
	    </listhead>
		
		<listitem style="white-space: nowrap">
			<listcell label="XXX" hflex="min" />
			<listcell label="XXX description" />
       </listitem>			
	</listbox>
</window>

simplified:

    <listbox>
        <listhead>
            <listheader label="Client" hflex="min"/>
        </listhead>
        <listitem>
            <listcell label="aaa" hflex="min"/>
        </listitem>
    </listbox>

Current Result

Data are either not displayed properly or even crash with:
Uncaught TypeError: Cannot read property 'firstChild' of null
at _calcMinWd (zul.mesh.wpd:62)
at init._calcMinWds (zul.mesh.wpd:1430)
at init.beforeMinFlex_ (zul.mesh.wpd:2917)
at Object.fixMinFlex (zk.wpd:27788)
at Object.fixFlex (zk.wpd:27678)
at init.onSize (zk.wpd:27583)
at _invoke (zk.wpd:15028)
at init.fire (zk.wpd:15011)
at _fire (zk.wpd:15154)
at Object.fireDown (zk.wpd:15371)

"Error code 3: ZK error, after mounting.
Something went wrong while loading the page."

Expected Result

• no error.
• show a non-native scrollbar

debug info

• since 8.5.2, there is no .z-listheader-bar rendered when navtivebar=false

Workaround

see attached zk-4071.js