OSM Map wasn't displayed anymore on many systems.

src/main/resources/eu/simstadt/regionchooser/website/script/simstadt_openlayers.js

@@ -24,7 +24,8 @@ const regionChooser = (function () {
 	}
 
 	var osm_layer = new ol.layer.Tile({
-		source: new ol.source.OSM()
+		// NOTE: when set to "anonymous" (the default), it could lead to the Browser not displaying any map
+		source: new ol.source.OSM({crossOrigin: null})
 	});
 
 	var kml_source = utils.read_kml(fromJavaFX ? undefined : 'data/citygml_hulls.kml');