Index: /trunk/src/org/openstreetmap/josm/actions/DownloadReferrersAction.java
===================================================================
--- /trunk/src/org/openstreetmap/josm/actions/DownloadReferrersAction.java	(revision 9880)
+++ /trunk/src/org/openstreetmap/josm/actions/DownloadReferrersAction.java	(revision 9881)
@@ -7,14 +7,10 @@
 import java.awt.event.ActionEvent;
 import java.awt.event.KeyEvent;
-import java.text.MessageFormat;
 import java.util.Collection;
-import java.util.Map;
 
 import org.openstreetmap.josm.Main;
 import org.openstreetmap.josm.actions.downloadtasks.DownloadReferrersTask;
 import org.openstreetmap.josm.data.osm.OsmPrimitive;
-import org.openstreetmap.josm.data.osm.OsmPrimitiveType;
 import org.openstreetmap.josm.gui.layer.OsmDataLayer;
-import org.openstreetmap.josm.tools.CheckParameterUtil;
 import org.openstreetmap.josm.tools.Shortcut;
 
@@ -47,37 +43,7 @@
      */
     public static void downloadReferrers(OsmDataLayer targetLayer, Collection<OsmPrimitive> children) {
-        if (children == null || children.isEmpty()) return;
+        if (children == null || children.isEmpty())
+            return;
         Main.worker.submit(new DownloadReferrersTask(targetLayer, children));
-    }
-
-    /**
-     * Downloads the primitives referring to the primitives in <code>primitives</code>
-     * into the target layer <code>targetLayer</code>.
-     * Does nothing if primitives is null or empty.
-     *
-     * @param targetLayer the target layer. Must not be null.
-     * @param children the collection of primitives, given as map of ids and types
-     * @throws IllegalArgumentException if targetLayer is null
-     */
-    public static void downloadReferrers(OsmDataLayer targetLayer, Map<Long, OsmPrimitiveType> children) {
-        if (children == null || children.isEmpty()) return;
-        Main.worker.submit(new DownloadReferrersTask(targetLayer, children));
-    }
-
-    /**
-     * Downloads the primitives referring to the primitive given by <code>id</code> and <code>type</code>.
-     *
-     * @param targetLayer the target layer. Must not be null.
-     * @param id the primitive id. id &gt; 0 required.
-     * @param type the primitive type. type != null required
-     * @throws IllegalArgumentException if targetLayer is null
-     * @throws IllegalArgumentException if id &lt;= 0
-     * @throws IllegalArgumentException if type == null
-     */
-    public static void downloadReferrers(OsmDataLayer targetLayer, long id, OsmPrimitiveType type) {
-        if (id <= 0)
-            throw new IllegalArgumentException(MessageFormat.format("Id > 0 required, got {0}", id));
-        CheckParameterUtil.ensureParameterNotNull(type, "type");
-        Main.worker.submit(new DownloadReferrersTask(targetLayer, id, type));
     }
 
Index: /trunk/src/org/openstreetmap/josm/actions/downloadtasks/DownloadReferrersTask.java
===================================================================
--- /trunk/src/org/openstreetmap/josm/actions/downloadtasks/DownloadReferrersTask.java	(revision 9880)
+++ /trunk/src/org/openstreetmap/josm/actions/downloadtasks/DownloadReferrersTask.java	(revision 9881)
@@ -71,62 +71,4 @@
         this.targetLayer = targetLayer;
         parents = new DataSet();
-    }
-
-    /**
-     * constructor
-     *
-     * @param targetLayer  the target layer for the downloaded primitives. Must not be null.
-     * @param children  the collection of children for which parents are to be downloaded. Children
-     * are specified by their id and  their type.
-     */
-    public DownloadReferrersTask(OsmDataLayer targetLayer, Map<Long, OsmPrimitiveType> children) {
-        super("Download referrers", false /* don't ignore exception*/);
-        CheckParameterUtil.ensureParameterNotNull(targetLayer, "targetLayer");
-        canceled = false;
-        this.children = new HashMap<>();
-        if (children != null) {
-            for (Entry<Long, OsmPrimitiveType> entry : children.entrySet()) {
-                if (entry.getKey() > 0 && entry.getValue() != null) {
-                    children.put(entry.getKey(), entry.getValue());
-                }
-            }
-        }
-        this.targetLayer = targetLayer;
-        parents = new DataSet();
-    }
-
-    /**
-     * constructor
-     *
-     * @param targetLayer  the target layer. Must not be null.
-     * @param id the primitive id. id &gt; 0 required.
-     * @param type the primitive type. type != null required
-     * @throws IllegalArgumentException if id &lt;= 0
-     * @throws IllegalArgumentException if type == null
-     * @throws IllegalArgumentException if targetLayer == null
-     */
-    public DownloadReferrersTask(OsmDataLayer targetLayer, long id, OsmPrimitiveType type) {
-        super("Download referrers", false /* don't ignore exception*/);
-        CheckParameterUtil.ensureParameterNotNull(targetLayer, "targetLayer");
-        if (id <= 0)
-            throw new IllegalArgumentException(MessageFormat.format("Id > 0 required, got {0}", id));
-        CheckParameterUtil.ensureParameterNotNull(type, "type");
-        canceled = false;
-        this.children = new HashMap<>();
-        this.children.put(id, type);
-        this.targetLayer = targetLayer;
-        parents = new DataSet();
-    }
-
-    /**
-     * constructor
-     *
-     * @param targetLayer the target layer. Must not be null.
-     * @param primitiveId a PrimitiveId object.
-     * @throws IllegalArgumentException if id &lt;= 0
-     * @throws IllegalArgumentException if targetLayer == null
-     */
-    public DownloadReferrersTask(OsmDataLayer targetLayer, PrimitiveId primitiveId) {
-        this(targetLayer,  primitiveId, null);
     }
 
Index: /trunk/test/unit/org/openstreetmap/josm/gui/layer/ValidatorLayerTest.java
===================================================================
--- /trunk/test/unit/org/openstreetmap/josm/gui/layer/ValidatorLayerTest.java	(revision 9881)
+++ /trunk/test/unit/org/openstreetmap/josm/gui/layer/ValidatorLayerTest.java	(revision 9881)
@@ -0,0 +1,48 @@
+// License: GPL. For details, see LICENSE file.
+package org.openstreetmap.josm.gui.layer;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertNotNull;
+import static org.junit.Assert.assertTrue;
+
+import org.junit.BeforeClass;
+import org.junit.Test;
+import org.openstreetmap.josm.JOSMFixture;
+import org.openstreetmap.josm.Main;
+
+/**
+ * Unit tests of {@link ValidatorLayer} class.
+ */
+public class ValidatorLayerTest {
+
+    /**
+     * Setup tests
+     */
+    @BeforeClass
+    public static void setUpBeforeClass() {
+        JOSMFixture.createUnitTestFixture().init(true);
+    }
+
+    /**
+     * Unit test of {@link ValidatorLayer#ValidatorLayer}.
+     */
+    @Test
+    public void testValidatorLayer() {
+        ValidatorLayer layer = null;
+        try {
+            layer = new ValidatorLayer();
+            Main.main.addLayer(layer);
+            assertFalse(layer.isMergable(null));
+            assertNotNull(layer.getIcon());
+            assertEquals("<html>No validation errors</html>", layer.getToolTipText());
+            assertEquals("<html>No validation errors</html>", layer.getInfoComponent());
+            assertTrue(layer.getMenuEntries().length > 0);
+        } finally {
+            // Ensure we clean the place before leaving, even if test fails.
+            if (layer != null) {
+                Main.main.removeLayer(layer);
+            }
+        }
+    }
+}