routing controls class

website/src/lib/components/gpx-layer/GPXLayers.svelte

@@ -7,12 +7,14 @@
 	let gpxLayers: Map<Writable<GPXFile>, GPXLayer> = new Map();
 
 	$: if ($map) {
+		// remove layers for deleted files
 		gpxLayers.forEach((layer, file) => {
 			if (!get(files).includes(file)) {
 				layer.remove();
 				gpxLayers.delete(file);
 			}
 		});
+		// add layers for new files
 		$files.forEach((file) => {
 			if (!gpxLayers.has(file)) {
 				gpxLayers.set(file, new GPXLayer(get(map), file));