Index: trunk/src/org/openstreetmap/josm/actions/JoinAreasAction.java
===================================================================
--- trunk/src/org/openstreetmap/josm/actions/JoinAreasAction.java	(revision 14134)
+++ trunk/src/org/openstreetmap/josm/actions/JoinAreasAction.java	(revision 14135)
@@ -41,5 +41,4 @@
 import org.openstreetmap.josm.data.osm.TagCollection;
 import org.openstreetmap.josm.data.osm.Way;
-import org.openstreetmap.josm.gui.MainApplication;
 import org.openstreetmap.josm.gui.Notification;
 import org.openstreetmap.josm.gui.conflict.tags.CombinePrimitiveResolverDialog;
@@ -1602,5 +1601,5 @@
         cmds.clear();
         if (Main.main != null && addUndoRedo) {
-            UndoRedoHandler ur = MainApplication.undoRedo;
+            UndoRedoHandler ur = UndoRedoHandler.getInstance();
             int i = Math.max(ur.commands.size() - cmdsCount, 0);
             for (; i < ur.commands.size(); i++) {
Index: trunk/src/org/openstreetmap/josm/gui/MainApplication.java
===================================================================
--- trunk/src/org/openstreetmap/josm/gui/MainApplication.java	(revision 14134)
+++ trunk/src/org/openstreetmap/josm/gui/MainApplication.java	(revision 14135)
@@ -251,5 +251,5 @@
             Layer layer = e.getRemovedLayer();
             if (layer instanceof OsmDataLayer) {
-                undoRedo.clean(((OsmDataLayer) layer).getDataSet());
+                UndoRedoHandler.getInstance().clean(((OsmDataLayer) layer).getDataSet());
             }
         }
@@ -415,5 +415,5 @@
             new InitializationTask(tr("Building main menu"), this::initializeMainWindow),
             new InitializationTask(tr("Updating user interface"), () -> {
-                undoRedo.addCommandQueueListener(redoUndoListener);
+                UndoRedoHandler.getInstance().addCommandQueueListener(redoUndoListener);
                 // creating toolbar
                 GuiHelper.runInEDTAndWait(() -> contentPanePrivate.add(toolbar.control, BorderLayout.NORTH));