Index: trunk/src/org/openstreetmap/josm/actions/MergeLayerAction.java
===================================================================
--- trunk/src/org/openstreetmap/josm/actions/MergeLayerAction.java	(revision 11289)
+++ trunk/src/org/openstreetmap/josm/actions/MergeLayerAction.java	(revision 11290)
@@ -18,4 +18,5 @@
 import org.openstreetmap.josm.tools.ImageProvider;
 import org.openstreetmap.josm.tools.Shortcut;
+import org.openstreetmap.josm.tools.Utils;
 
 /**
@@ -41,5 +42,7 @@
         if (targetLayer == null)
             return;
+        final Object actionName = MergeLayerAction.this.getValue(NAME);
         Main.worker.submit(() -> {
+                final long start = System.currentTimeMillis();
                 boolean layerMerged = false;
                 for (final Layer sourceLayer: sourceLayers) {
@@ -59,4 +62,5 @@
                 if (layerMerged) {
                     Main.getLayerManager().setActiveLayer(targetLayer);
+                    Main.info(tr("{0} completed in {1}", actionName, Utils.getDurationString(System.currentTimeMillis() - start)));
                 }
         });