Steps to Reproduce

    <groupbox id="groupbox">
        <caption id="caption" hflex="min" >
            Caption
        </caption>
        <div id="div" hflex="min">
            data
        </div>
    </groupbox>

Current Result

Uncaught TypeError: Cannot set properties of undefined (setting 'minFlexInfoList')
at init.applyCSSFlex (zk.wpd:32019:81)
at _invoke (zk.wpd:15655:14)
at init.fire (zk.wpd:15641:9)
at _fire (zk.wpd:15798:13)
at Object.fireDown (zk.wpd:16031:7)
at Object.fireSized (zk.wpd:18853:16)
at init.replaceHTML (zk.wpd:22982:43)
at mtBL0 (zk.wpd:27390:13)
at mtBL (zk.wpd:27356:5)
at zkx (zk.wpd:27682:11)

Expected Result

no error

Debug Information

Workaround

• remove hflex="min"
• <custom-attributes org.zkoss.zul.css.flex="false"/> inside <caption/>