Index: /trunk/src/org/openstreetmap/josm/gui/download/OverpassQueryWizardDialog.java
===================================================================
--- /trunk/src/org/openstreetmap/josm/gui/download/OverpassQueryWizardDialog.java	(revision 18217)
+++ /trunk/src/org/openstreetmap/josm/gui/download/OverpassQueryWizardDialog.java	(revision 18218)
@@ -85,5 +85,6 @@
      */
     private void saveHistory() {
-        model.addTopElement(SearchSetting.fromString(hcbSearchString.getText()));
+        Optional.ofNullable(SearchSetting.fromString(hcbSearchString.getText()))
+            .ifPresent(model::addTopElement);
         prefs.save(OVERPASS_WIZARD_HISTORY);
     }