Index: /trunk/src/org/openstreetmap/josm/data/validation/tests/MapCSSTagChecker.java
===================================================================
--- /trunk/src/org/openstreetmap/josm/data/validation/tests/MapCSSTagChecker.java	(revision 17010)
+++ /trunk/src/org/openstreetmap/josm/data/validation/tests/MapCSSTagChecker.java	(revision 17011)
@@ -458,5 +458,5 @@
          */
         Command fixPrimitive(OsmPrimitive p) {
-            if (fixCommands.isEmpty() && !deletion) {
+            if (p.getDataSet() == null || (fixCommands.isEmpty() && !deletion)) {
                 return null;
             }