Index: trunk/src/org/openstreetmap/josm/data/osm/OsmPrimitive.java
===================================================================
--- trunk/src/org/openstreetmap/josm/data/osm/OsmPrimitive.java	(revision 2582)
+++ trunk/src/org/openstreetmap/josm/data/osm/OsmPrimitive.java	(revision 2583)
@@ -890,6 +890,9 @@
         List<OsmPrimitive> result = new ArrayList<OsmPrimitive>();
         if (referrers != null) {
-            if ((referrers instanceof OsmPrimitive) && (((OsmPrimitive)referrers).dataSet == dataSet)) {
-                result.add((OsmPrimitive)referrers);
+            if (referrers instanceof OsmPrimitive) {
+                OsmPrimitive ref = (OsmPrimitive)referrers;
+                if (ref.dataSet == dataSet) {
+                    result.add(ref);
+                }
             } else {
                 for (OsmPrimitive o:(OsmPrimitive[])referrers) {