Index: trunk/src/org/openstreetmap/josm/gui/dialogs/HistoryDialog.java
===================================================================
--- trunk/src/org/openstreetmap/josm/gui/dialogs/HistoryDialog.java	(revision 3643)
+++ trunk/src/org/openstreetmap/josm/gui/dialogs/HistoryDialog.java	(revision 3645)
@@ -141,4 +141,9 @@
         HistoryDataSet.getInstance().addHistoryDataSetListener(this);
         DataSet.addSelectionListener(model);
+        if (Main.main.getCurrentDataSet() == null) {
+            model.selectionChanged(null);
+        } else {
+            model.selectionChanged(Main.main.getCurrentDataSet().getSelected());
+        }
     }