Index: trunk/src/org/openstreetmap/josm/actions/StopChangesetAction.java
===================================================================
--- trunk/src/org/openstreetmap/josm/actions/StopChangesetAction.java	(revision 2058)
+++ trunk/src/org/openstreetmap/josm/actions/StopChangesetAction.java	(revision 2058)
@@ -0,0 +1,89 @@
+// License: GPL. For details, see LICENSE file.
+package org.openstreetmap.josm.actions;
+
+import java.awt.event.ActionEvent;
+import java.awt.event.KeyEvent;
+import java.io.IOException;
+
+import javax.swing.JOptionPane;
+
+import org.openstreetmap.josm.Main;
+import org.openstreetmap.josm.gui.ExceptionDialogUtil;
+import org.openstreetmap.josm.gui.PleaseWaitRunnable;
+import org.openstreetmap.josm.io.ChangesetProcessingType;
+import org.openstreetmap.josm.io.OsmApi;
+import org.openstreetmap.josm.io.OsmTransferException;
+import org.openstreetmap.josm.tools.Shortcut;
+import org.xml.sax.SAXException;
+
+import static org.openstreetmap.josm.tools.I18n.tr;
+
+public class StopChangesetAction extends JosmAction{
+
+    public StopChangesetAction() {
+        super(tr("Close current changeset"),
+                "closechangeset",
+                tr("Close the current changeset ..."),
+                Shortcut.registerShortcut(
+                        "system:closechangeset",
+                        tr("File: {0}", tr("Close the current changeset ...")),
+                        KeyEvent.VK_O,
+                        Shortcut.GROUP_MENU
+                ),
+                true
+        );
+
+    }
+    public void actionPerformed(ActionEvent e) {
+        if (OsmApi.getOsmApi().getCurrentChangeset() == null) {
+            JOptionPane.showMessageDialog(
+                    Main.parent,
+                    tr("There is currently no changeset open."),
+                    tr("No open changeset"),
+                    JOptionPane.INFORMATION_MESSAGE
+            );
+            return;
+        }
+        Main.worker.submit(new StopChangesetActionTask());
+    }
+
+    @Override
+    protected void updateEnabledState() {
+        setEnabled(Main.map != null && OsmApi.getOsmApi().getCurrentChangeset() != null);
+    }
+
+    static class StopChangesetActionTask extends PleaseWaitRunnable {
+        private boolean cancelled;
+        private Exception lastException;
+
+        public StopChangesetActionTask() {
+            super(tr("Closing changeset"), false /* don't ignore exceptions */);
+        }
+        @Override
+        protected void cancel() {
+            this.cancelled = true;
+            OsmApi.getOsmApi().cancel();
+
+        }
+
+        @Override
+        protected void finish() {
+            if (cancelled)
+                return;
+            if (lastException != null) {
+                ExceptionDialogUtil.explainException(lastException);
+            }
+        }
+
+        @Override
+        protected void realRun() throws SAXException, IOException, OsmTransferException {
+            try {
+                OsmApi.getOsmApi().stopChangeset(ChangesetProcessingType.USE_EXISTING_AND_CLOSE, getProgressMonitor().createSubTaskMonitor(1, false));
+            } catch(Exception e) {
+                if (cancelled)
+                    return;
+                lastException = e;
+            }
+        }
+    }
+}
Index: trunk/src/org/openstreetmap/josm/actions/UploadAction.java
===================================================================
--- trunk/src/org/openstreetmap/josm/actions/UploadAction.java	(revision 2057)
+++ trunk/src/org/openstreetmap/josm/actions/UploadAction.java	(revision 2058)
@@ -57,6 +57,4 @@
 import org.openstreetmap.josm.tools.WindowGeometry;
 import org.xml.sax.SAXException;
-
-import com.sun.corba.se.spi.orbutil.fsm.Action;
 
 
@@ -757,4 +755,6 @@
 
         public boolean hasChangesetComment() {
+            if (!getChangesetProcessingType().isUseNew())
+                return true;
             return cmt.getText().trim().length() >= 3;
         }