Index: trunk/src/org/openstreetmap/josm/data/UndoRedoHandler.java
===================================================================
--- trunk/src/org/openstreetmap/josm/data/UndoRedoHandler.java	(revision 17378)
+++ trunk/src/org/openstreetmap/josm/data/UndoRedoHandler.java	(revision 17379)
@@ -470,5 +470,5 @@
      * @since 12718
      */
-    public synchronized void clean(DataSet dataSet) {
+    public static synchronized void clean(DataSet dataSet) {
         if (dataSet == null)
             return;
Index: trunk/src/org/openstreetmap/josm/gui/MainApplication.java
===================================================================
--- trunk/src/org/openstreetmap/josm/gui/MainApplication.java	(revision 17378)
+++ trunk/src/org/openstreetmap/josm/gui/MainApplication.java	(revision 17379)
@@ -222,5 +222,5 @@
             Layer layer = e.getRemovedLayer();
             if (layer instanceof OsmDataLayer) {
-                UndoRedoHandler.getInstance().clean(((OsmDataLayer) layer).getDataSet());
+                UndoRedoHandler.clean(((OsmDataLayer) layer).getDataSet());
             }
         }
Index: trunk/src/org/openstreetmap/josm/gui/io/AsynchronousUploadPrimitivesTask.java
===================================================================
--- trunk/src/org/openstreetmap/josm/gui/io/AsynchronousUploadPrimitivesTask.java	(revision 17378)
+++ trunk/src/org/openstreetmap/josm/gui/io/AsynchronousUploadPrimitivesTask.java	(revision 17379)
@@ -121,5 +121,5 @@
         GuiHelper.runInEDTAndWait(() -> {
             // Remove the commands from the undo stack
-            UndoRedoHandler.getInstance().clean(uploadDataLayer.getDataSet());
+            UndoRedoHandler.clean(uploadDataLayer.getDataSet());
             MainApplication.getLayerManager().prepareLayerForUpload(uploadDataLayer);
 
Index: trunk/src/org/openstreetmap/josm/gui/layer/OsmDataLayer.java
===================================================================
--- trunk/src/org/openstreetmap/josm/gui/layer/OsmDataLayer.java	(revision 17378)
+++ trunk/src/org/openstreetmap/josm/gui/layer/OsmDataLayer.java	(revision 17379)
@@ -654,5 +654,5 @@
             return;
 
-        UndoRedoHandler.getInstance().clean(data);
+        UndoRedoHandler.clean(data);
 
         // if uploaded, clean the modified flags as well