Index: /trunk/src/org/openstreetmap/josm/gui/dialogs/relation/GenericRelationEditor.java
===================================================================
--- /trunk/src/org/openstreetmap/josm/gui/dialogs/relation/GenericRelationEditor.java	(revision 2580)
+++ /trunk/src/org/openstreetmap/josm/gui/dialogs/relation/GenericRelationEditor.java	(revision 2581)
@@ -450,4 +450,5 @@
         // -- sort action
         SortAction sortAction = new SortAction();
+        memberTableModel.addTableModelListener(sortAction);
         tb.add(sortAction);
 
@@ -866,5 +867,5 @@
     }
 
-    class SortAction extends AbstractAction implements ListSelectionListener {
+    class SortAction extends AbstractAction implements TableModelListener {
         public SortAction() {
             putValue(SHORT_DESCRIPTION, tr("Sort the relation members"));
@@ -881,8 +882,8 @@
 
         protected void updateEnabledState() {
-            setEnabled(memberTable.getSelectedRowCount() > 0);
-        }
-
-        public void valueChanged(ListSelectionEvent e) {
+            setEnabled(memberTableModel.getRowCount() > 0);
+        }
+
+        public void tableChanged(TableModelEvent e) {
             updateEnabledState();
         }