Index: /applications/editors/josm/plugins/wmsplugin/src/wmsplugin/WMSLayer.java
===================================================================
--- /applications/editors/josm/plugins/wmsplugin/src/wmsplugin/WMSLayer.java	(revision 6308)
+++ /applications/editors/josm/plugins/wmsplugin/src/wmsplugin/WMSLayer.java	(revision 6309)
@@ -167,4 +167,5 @@
 		public void actionPerformed(ActionEvent ev) {
 			File f = openFileDialog(true);
+			if (f == null) return;
 			try {
 				FileInputStream fis = new FileInputStream(f);