Index: trunk/src/org/openstreetmap/josm/gui/dialogs/relation/ChildRelationBrowser.java
===================================================================
--- trunk/src/org/openstreetmap/josm/gui/dialogs/relation/ChildRelationBrowser.java	(revision 14276)
+++ trunk/src/org/openstreetmap/josm/gui/dialogs/relation/ChildRelationBrowser.java	(revision 14277)
@@ -97,5 +97,5 @@
                     && childTree.getRowForLocation(e.getX(), e.getY()) == childTree.getMinSelectionRow()) {
                     Relation r = (Relation) childTree.getLastSelectedPathComponent();
-                    if (r.isIncomplete()) {
+                    if (r != null && r.isIncomplete()) {
                         childTree.expandPath(childTree.getSelectionPath());
                     } else {