It is safer to put the layers to null on the deactivation method.
It is safer to put the layers to null on the deactivation method.

marcjansen/OL-DynamicMeasure,marcjansen/OL-DynamicMeasure,neogis-de/OL-DynamicMeasure,neogis-de/OL-DynamicMeasure,jorix/OL-DynamicMeasure