WICKET-5104 AjaxSelfUpdatingTimerBehavior in hidden component in ModalWindow causes Ajax Response Error
Fix a minor typo in comment
WICKET-5125 IE8 error in wicket-date.js when used in a modalwindow

Add a check for existance of YAHOO.wicket[cfg.dpJs]
WICKET-5121 Log warning message if a component that is not on the page associated with the AjaxRequestTarget is added