Index: src/org/openstreetmap/josm/gui/dialogs/properties/TagEditHelper.java
===================================================================
--- src/org/openstreetmap/josm/gui/dialogs/properties/TagEditHelper.java	(revision 8189)
+++ src/org/openstreetmap/josm/gui/dialogs/properties/TagEditHelper.java	(working copy)
@@ -635,7 +635,10 @@
 
         private void selectNumberOfTags() {
             String s = JOptionPane.showInputDialog(this, tr("Please enter the number of recently added tags to display"));
-            if (s!=null) try {
+            if (s==null) {
+                return;
+            }
+            try {
                 int v = Integer.parseInt(s);
                 if (v>=0 && v<=MAX_LRU_TAGS_NUMBER) {
                     PROPERTY_RECENT_TAGS_NUMBER.put(v);