Index: /applications/editors/josm/plugins/validator/src/org/openstreetmap/josm/plugins/validator/ErrorTreePanel.java
===================================================================
--- /applications/editors/josm/plugins/validator/src/org/openstreetmap/josm/plugins/validator/ErrorTreePanel.java	(revision 10665)
+++ /applications/editors/josm/plugins/validator/src/org/openstreetmap/josm/plugins/validator/ErrorTreePanel.java	(revision 10666)
@@ -223,5 +223,9 @@
 					// Message node
 					List<TestError> errors = msgErrors.getValue();
-					String msg = msgErrors.getKey() + " (" + errors.size() + ")";
+					String msg;
+					if(groupNode != null)
+						msg = msgErrors.getKey() + " (" + errors.size() + ")";
+					else
+						msg = msgErrors.getKey() + " - " + bag.getKey() + " (" + errors.size() + ")";
 					DefaultMutableTreeNode messageNode = new DefaultMutableTreeNode(msg);
 					if(groupNode != null)
Index: /applications/editors/josm/plugins/validator/src/org/openstreetmap/josm/plugins/validator/tests/TagChecker.java
===================================================================
--- /applications/editors/josm/plugins/validator/src/org/openstreetmap/josm/plugins/validator/tests/TagChecker.java	(revision 10665)
+++ /applications/editors/josm/plugins/validator/src/org/openstreetmap/josm/plugins/validator/tests/TagChecker.java	(revision 10666)
@@ -352,6 +352,7 @@
 				if( values != null && !values.contains(prop.getValue()) && !withErrors.contains(p, "UPV"))
 				{
+					String i = marktr("Key ''{0}'' unknown.");
 					errors.add( new TestError(this, Severity.OTHER, tr("Unknown property values"),
-					tr(s, key), MessageFormat.format(s, key), INVALID_VALUE, p) );
+					tr(i, key), MessageFormat.format(i, key), INVALID_VALUE, p) );
 					withErrors.add(p, "UPV");
 				}