Index: src/org/openstreetmap/josm/Main.java
===================================================================
--- src/org/openstreetmap/josm/Main.java	(revision 4898)
+++ src/org/openstreetmap/josm/Main.java	(working copy)
@@ -587,7 +587,7 @@
         SaveLayersDialog dialog = new SaveLayersDialog(Main.parent);
         List<OsmDataLayer> layersWithUnmodifiedChanges = new ArrayList<OsmDataLayer>();
         for (OsmDataLayer l: Main.map.mapView.getLayersOfType(OsmDataLayer.class)) {
-            if (l.requiresSaveToFile() || l.requiresUploadToServer()) {
+            if ((l.requiresSaveToFile() || l.requiresUploadToServer()) && l.data.isModified()) {
                 layersWithUnmodifiedChanges.add(l);
             }
         }