Index: trunk/src/org/openstreetmap/josm/gui/dialogs/RelationListDialog.java
===================================================================
--- trunk/src/org/openstreetmap/josm/gui/dialogs/RelationListDialog.java	(revision 2502)
+++ trunk/src/org/openstreetmap/josm/gui/dialogs/RelationListDialog.java	(revision 2503)
@@ -511,4 +511,5 @@
      */
     private static  class RelationListModel extends AbstractListModel {
+        /** the list of relations managaged by this model. Should never be null */
         private ArrayList<Relation> relations;
         private DefaultListSelectionModel selectionModel;
@@ -516,4 +517,5 @@
         public RelationListModel(DefaultListSelectionModel selectionModel) {
             this.selectionModel = selectionModel;
+            relations = new ArrayList<Relation>();
         }
 
@@ -525,5 +527,5 @@
             List<Relation> sel =  getSelectedRelations();
             if (relations == null) {
-                this.relations = null;
+                this.relations.clear();
             } else {
                 this.relations = new ArrayList<Relation>(relations.size());
@@ -540,5 +542,4 @@
 
         public synchronized void sort() {
-            if (relations == null) return;
             Collections.sort(
                     relations,
@@ -563,4 +564,7 @@
             if (addedPrimitives == null || addedPrimitives.isEmpty()) return;
             boolean added = false;
+            if (relations == null) {
+                relations = new ArrayList<Relation>();
+            }
             for (OsmPrimitive p: addedPrimitives) {
                 if (! (p instanceof Relation)) {
@@ -611,10 +615,8 @@
 
         public Object getElementAt(int index) {
-            if (relations == null) return null;
             return relations.get(index);
         }
 
         public int getSize() {
-            if (relations == null) return 0;
             return relations.size();
         }
@@ -628,5 +630,4 @@
         public List<Relation> getSelectedNonNewRelations() {
             ArrayList<Relation> ret = new ArrayList<Relation>();
-            if (relations == null) return ret;
             for (int i=0; i<getSize();i++) {
                 if (!selectionModel.isSelectedIndex(i)) {
@@ -649,5 +650,4 @@
         public List<Relation> getSelectedRelations() {
             ArrayList<Relation> ret = new ArrayList<Relation>();
-            if (relations == null) return ret;
             for (int i=0; i<getSize();i++) {
                 if (!selectionModel.isSelectedIndex(i)) {