Index: /trunk/src/org/openstreetmap/josm/data/osm/Node.java
===================================================================
--- /trunk/src/org/openstreetmap/josm/data/osm/Node.java	(revision 5913)
+++ /trunk/src/org/openstreetmap/josm/data/osm/Node.java	(revision 5914)
@@ -113,4 +113,5 @@
             this.lon = Double.NaN;
             invalidateEastNorthCache();
+            setIncomplete(true);
         }
     }