Index: /trunk/src/org/openstreetmap/josm/gui/dialogs/relation/RelationEditor.java
===================================================================
--- /trunk/src/org/openstreetmap/josm/gui/dialogs/relation/RelationEditor.java	(revision 1870)
+++ /trunk/src/org/openstreetmap/josm/gui/dialogs/relation/RelationEditor.java	(revision 1871)
@@ -106,5 +106,5 @@
         );
         if (layer == null)
-            throw new IllegalArgumentException(tr("parameter ''layer'' must not be null", "layer"));
+            throw new IllegalArgumentException(tr("parameter ''{0}'' must not be null", "layer"));
         this.layer = layer;
         setRelation(relation);