A wiki component listener can become a ghost if it's listening to an event from an installed extension

When an extension is uninstall/upgrade on a namespace all the classes of that namespace (and child namespaces) are re-created and all components in those namespaces reloaded... except wiki components.

The problem is that the wiki component listener was registered with the old event Class and even if the class name did not change it's not technically the same one, so the listener is never matched anymore after the reload.

Java component coming from extensions are not impacted by this problem because all the Java component of JAR extensions installed in the reloaded namespace are reloaded too.