Index: src/org/openstreetmap/josm/gui/dialogs/relation/GenericRelationEditor.java
===================================================================
--- src/org/openstreetmap/josm/gui/dialogs/relation/GenericRelationEditor.java	(revision 1620)
+++ src/org/openstreetmap/josm/gui/dialogs/relation/GenericRelationEditor.java	(working copy)
@@ -345,6 +345,8 @@
                     way1 = m;
                     break;
                 } else if (m.member instanceof Relation) {
+                    if (m.member == this.relation)
+                        break;
                     m = ((Relation)m.member).lastMember();
                 } else {
                     break;
@@ -359,6 +361,8 @@
                             way2 = m;
                             break;
                         } else if (m.member instanceof Relation) {
+                            if (m.member == this.relation)
+                                break;
                             m = ((Relation)(m.member)).firstMember();
                         } else {
                             break;