Steps to Reproduce

https://zkfiddle.org/sample/25s2fmq/1-Another-new-ZK-fiddle

Run fiddle

Click button

Current Result

Ui is stuck in infinite fireSized loop

Expected Result

ClientInfo event is resolved and output to log

Debug Information

Most likely Introduced by  https://tracker.zkoss.org/browse/ZK-4601

(not confirmed which part, but starts to fails on this freshly. Also bug doesn't seem to happen without tabpanel)

Require the tabpanel to add a new include in defer mode.

New include in defer mode must request clientInfo

https://github.com/zkoss/zk/blob/363fade7ce1f4de9189a8f2ca0a08da6dfeeeecb/zk/src/archive/web/js/zk/utl.js#L640-L645

This block will loop waiting for zk.clientinfo to become not true by calling itself with a 20ms delay.

For some reason, zk.clientinfo never becomes not true after this commit, causing the loop to never exit

Workaround

disable client ROD on tabbox

<tabbox>
    <custom-attributes org.zkoss.zul.client.rod="false"/>