IEditManager editManager=handler.getContext().getEditManager();
// add listener if editManager is not null and map blackboard indicates that a listener has not be previously added
if ( getRegisteredListener(editManager)==null ) {
EditManagerListener editManagerListener = new EditManagerListener(editManager,handler);
editManager.addListener(editManagerListener);
editManager.getMap().getBlackboard().put(EDITING_EDIT_MANAGER_LISTENER, editManagerListener);
}else{
getRegisteredListener(editManager).handler=handler;
}
}