Index: applications/editors/josm/plugins/wikipedia/src/org/wikipedia/gui/WikipediaToggleDialog.java
===================================================================
--- applications/editors/josm/plugins/wikipedia/src/org/wikipedia/gui/WikipediaToggleDialog.java	(revision 34092)
+++ applications/editors/josm/plugins/wikipedia/src/org/wikipedia/gui/WikipediaToggleDialog.java	(revision 34093)
@@ -27,4 +27,5 @@
 import org.openstreetmap.josm.command.ChangePropertyCommand;
 import org.openstreetmap.josm.data.coor.LatLon;
+import org.openstreetmap.josm.data.osm.DataSet;
 import org.openstreetmap.josm.data.osm.OsmPrimitive;
 import org.openstreetmap.josm.data.osm.Tag;
@@ -316,8 +317,9 @@
 
         static void addTag(Tag tag) {
-            if (tag == null) {
-                return;
-            }
-            final Collection<OsmPrimitive> selected = MainApplication.getLayerManager().getEditDataSet().getSelected();
+            final DataSet editDataSet = MainApplication.getLayerManager().getEditDataSet();
+            if (tag == null || editDataSet == null) {
+                return;
+            }
+            final Collection<OsmPrimitive> selected = editDataSet.getSelected();
             if (selected.isEmpty() || !GuiUtils.confirmOverwrite(tag.getKey(), tag.getValue(), selected)) {
                 return;