Index: applications/editors/josm/plugins/utilsplugin/src/UtilsPlugin/JoinAreasAction.java
===================================================================
--- applications/editors/josm/plugins/utilsplugin/src/UtilsPlugin/JoinAreasAction.java	(revision 18297)
+++ applications/editors/josm/plugins/utilsplugin/src/UtilsPlugin/JoinAreasAction.java	(revision 18387)
@@ -170,5 +170,6 @@
         if(joinAreas(selWays[0], selWays[ways == 2 ? 1 : 0])) {
             Main.map.mapView.repaint();
-            DataSet.fireSelectionChanged(Main.main.getCurrentDataSet().getSelected());
+            DataSet ds = Main.main.getCurrentDataSet();
+            ds.fireSelectionChanged();
         } else
             JOptionPane.showMessageDialog(Main.parent, tr("No intersection found. Nothing was changed."));