Index: trunk/src/org/openstreetmap/josm/io/OsmWriter.java
===================================================================
--- trunk/src/org/openstreetmap/josm/io/OsmWriter.java	(revision 1734)
+++ trunk/src/org/openstreetmap/josm/io/OsmWriter.java	(revision 1735)
@@ -169,5 +169,5 @@
             }
             for (Entry<String, String> e : osm.keys.entrySet()) {
-                if (!("created_by".equals(e.getKey())))
+                if ((osm instanceof Changeset) || !("created_by".equals(e.getKey())))
                     out.println("    <tag k='"+ XmlWriter.encode(e.getKey()) +
                             "' v='"+XmlWriter.encode(e.getValue())+ "' />");