Refresh style.

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

-var regionChooser = (function(){
+const styles = {};
+
+styles.original = utils.polygon_style('#447744', 0.2);
+styles.highlighted = utils.polygon_style("#ff44a2", 0.7);
+styles.selected = utils.polygon_style("#ffff00", 0.8);
+
+const regionChooser = (function(){
 	//TODO: Somehow split in classes. This file is getting too big and mixed
 	var publicScope = {};
 	const fromJavaFX = navigator.userAgent.indexOf('JavaFX') !== -1;
@@ -26,7 +32,7 @@ var regionChooser = (function(){
 
 	var kml_layer = new ol.layer.Vector({
 		source : kml_source,
-		style : utils.polygon_style('#447744', 0.2)
+		style : styles.original
 	});
 
 	var intersections = new ol.source.Vector();
@@ -74,7 +80,7 @@ var regionChooser = (function(){
 			feature["project"] = feature.get("project");
 			feature["name"] = feature.get("name");
 			feature["source"] = "CityGML";
-			feature["originalStyle"] = feature.getStyle();
+			feature["status"] = "original";
 		});
 		
 		var features = Array.from(kml_source.getFeatures());
@@ -160,22 +166,26 @@ var regionChooser = (function(){
 	
 	publicScope.highlightPolygon = function(i) {
 		var feature = kml_source.getFeatureById(i);
-		feature.setStyle(utils.polygon_style("#ff44a2", 0.7));
+		feature.setStyle(styles.highlighted);
 	}
 	
 	publicScope.resetHighlight = function(i) {
 		var feature = kml_source.getFeatureById(i);
-		feature.setStyle(feature.originalStyle);
+		refreshStyle(feature);
+	}
+	
+	refreshStyle = function(feature){
+		feature.setStyle(styles[feature.status]);
 	}
 	
 	publicScope.isDownloadPossible = function(){
-		kml_source.getFeatures().forEach(f => f.setStyle(f.originalStyle));
+		kml_source.getFeatures().forEach(f => {f.status = "original"; refreshStyle(f)});
 		
 		//TODO: Dry
 		var checkedBoxes = Array.from(document.querySelectorAll("input.select_citygml")).filter(c => c.checked);
 		var checkbox_ids = checkedBoxes.map(c => c.id);
 		var features = getCheckedPolygons(checkbox_ids);
-		features.forEach(f => f.setStyle(utils.polygon_style("#ffff00", 0.8)));
+		features.forEach(f => {f.status = "selected"; refreshStyle(f)});
 		
 		document.getElementById("download_region_button").disabled = (checkedBoxes.length == 0);
 	}