Index: trunk/src/org/openstreetmap/josm/data/osm/AbstractPrimitive.java
===================================================================
--- trunk/src/org/openstreetmap/josm/data/osm/AbstractPrimitive.java	(revision 17586)
+++ trunk/src/org/openstreetmap/josm/data/osm/AbstractPrimitive.java	(revision 17587)
@@ -650,5 +650,5 @@
             return Collections.emptySet();
         }
-        if (keys.length == 1) {
+        if (keys.length == 2) {
             return Collections.singleton(keys[0]);
         }
@@ -666,5 +666,5 @@
         if (k == null) {
             return Stream.empty();
-        } else if (k.length == 1) {
+        } else if (k.length == 2) {
             return Stream.of(k[0]);
         } else {