Steps to Reproduce

Run fiddle

https://zkfiddle.org/sample/1bh8for/2-radiogroup-detach-removes-selectedIndex

click button

Current Result

Selected index in radiogroup is set to -1 while detached (because Radio#onPageDetached fires, causes selected index to set to -1 in radiogroup during Radiogroup#fixOnRemove)

Selected index remain -1 after component is reattached (because Radio#onPageAttached fires, but doesn't trigger Radiogroup#fixOnAdd)

Expected Result

When reattached to the same radiogroup, the selected radio should trigger radiogroup#fixOnAdd

Debug Information

Radiogroup#onPageAttached has following condition to trigger fixOnAdd:

 if (rg != null && rootParent instanceof ComponentCtrl if (rg != null && rootParent instanceof ComponentCtrl && (!Components.isAncestor(rootParent, rg) || rootParent == rg)) {

https://github.com/zkoss/zk/blob/master/zul/src/org/zkoss/zul/Radio.java#L299-L300

will only fire is the radiogroup is not a descendant of the rootParent, or if rootParent is the radiogroup.

If the radiogroup is a descendant of rootParent (as per fiddle), fixOnAdd doesn't trigger.

Workaround

attached java class RadioExt.java.

deploy globally with lang-addon:

	<component>
		<component-name>radio</component-name>
		<extends>radio</extends>
		<component-class>org.zkoss.zul.RadioExt</component-class>
	</component>