Index: trunk/src/org/openstreetmap/josm/gui/history/VersionInfoPanel.java
===================================================================
--- trunk/src/org/openstreetmap/josm/gui/history/VersionInfoPanel.java	(revision 5927)
+++ trunk/src/org/openstreetmap/josm/gui/history/VersionInfoPanel.java	(revision 5929)
@@ -94,13 +94,18 @@
                     );
         } else {
+            String date = "?";
+            if (primitive.getTimestamp() != null) {
+                date = DateFormat.getDateTimeInstance(DateFormat.SHORT, DateFormat.SHORT).format(primitive.getTimestamp());
+            }
             text = tr(
                     "<html>Version <strong>{0}</strong> created on <strong>{1}</strong></html>",
-                    Long.toString(primitive.getVersion()),
-                    DateFormat.getDateTimeInstance(DateFormat.SHORT, DateFormat.SHORT).format(primitive.getTimestamp())
-                    );
+                    Long.toString(primitive.getVersion()), date);
         }
         return text;
     }
 
+    /**
+     * Constructs a new {@code VersionInfoPanel}.
+     */
     public VersionInfoPanel() {
         pointInTimeType = null;
