Index: /trunk/src/org/openstreetmap/josm/gui/dialogs/RelationListDialog.java
===================================================================
--- /trunk/src/org/openstreetmap/josm/gui/dialogs/RelationListDialog.java	(revision 10860)
+++ /trunk/src/org/openstreetmap/josm/gui/dialogs/RelationListDialog.java	(revision 10861)
@@ -193,4 +193,10 @@
     }
 
+    @Override
+    public void destroy() {
+        model.clear();
+        super.destroy();
+    }
+
     public void enableRecentRelations() {
         recentRelationsAction.enableArrow();
@@ -392,4 +398,11 @@
         RelationListModel(DefaultListSelectionModel selectionModel) {
             this.selectionModel = selectionModel;
+        }
+
+        public void clear() {
+            relations.clear();
+            if (filteredRelations != null)
+                filteredRelations.clear();
+            filter = null;
         }