code: protected void fireLayerRemoveAllEvent(List<? extends L> removedObjects) {
  		fireLayerHierarchyChangedEvent(
  				new MapLayerHierarchyEvent(
  						this,
  						removedObjects,
  						Type.REMOVE_ALL_CHILDREN,
  						-1,
  						isTemporaryLayer()));
  	}
docs: Fire the event that indicates all the layers were removed.
  @param removedObjects are the removed objects.