Index: trunk/src/org/openstreetmap/josm/gui/dialogs/relation/GenericRelationEditor.java
===================================================================
--- trunk/src/org/openstreetmap/josm/gui/dialogs/relation/GenericRelationEditor.java	(revision 9437)
+++ trunk/src/org/openstreetmap/josm/gui/dialogs/relation/GenericRelationEditor.java	(revision 9438)
@@ -9,4 +9,5 @@
 import java.awt.Dimension;
 import java.awt.FlowLayout;
+import java.awt.GraphicsEnvironment;
 import java.awt.GridBagConstraints;
 import java.awt.GridBagLayout;
@@ -770,5 +771,7 @@
             for (OsmPrimitive p : primitivesToAdd) {
                 if (p instanceof Relation && orig.equals(p)) {
-                    warnOfCircularReferences(p);
+                    if (!GraphicsEnvironment.isHeadless()) {
+                        warnOfCircularReferences(p);
+                    }
                     continue;
                 } else if (MemberTableModel.hasMembersReferringTo(relation.getMembers(), Collections.singleton(p))