code: public void onGeometryEditStart(GeometryEditStartEvent event) {
  		if (container != null) {
  			mapPresenter.getContainerManager().removeVectorContainer(container);
  		}
  		container = mapPresenter.getContainerManager().addScreenContainer();
  		redraw();
  	}
docs: Clean up the previous state, create a container to draw in and then draw the geometry.