Errors logged when running in Wicket Development mode

When using the document picker while running in Wicket development mode, errors with long stack traces are logged:

ERROR http-nio-9080-exec-9 [JavaSerializer$SerializationCheckerObjectOutputStream.writeObjectOverride:290] error writing object [Page class = org.hippoecm.frontend.PluginPage, id = 1, render count = 1]: Stopped plugin is still being referenced: org.hippoecm.frontend.plugins.cms.browse.Navigator
[INFO] [talledLocalContainer] org.apache.wicket.WicketRuntimeException: Stopped plugin is still being referenced: org.hippoecm.frontend.plugins.cms.browse.Navigator
[INFO] [talledLocalContainer] at org.hippoecm.frontend.plugin.impl.PluginContext.writeObject(PluginContext.java:419)