Index: trunk/src/org/openstreetmap/josm/gui/history/VersionInfoPanel.java
===================================================================
--- trunk/src/org/openstreetmap/josm/gui/history/VersionInfoPanel.java	(revision 13013)
+++ trunk/src/org/openstreetmap/josm/gui/history/VersionInfoPanel.java	(revision 13014)
@@ -116,8 +116,10 @@
         final BasicArrowButton arrowButton = new BasicArrowButton(BasicArrowButton.SOUTH);
         arrowButton.addActionListener(action -> {
-            final OpenChangesetPopupMenu popupMenu = new OpenChangesetPopupMenu(changesetDialogAction.id);
-            popupMenu.insert(changesetDialogAction, 0);
-            ((AbstractButton) popupMenu.getComponent(0)).setText(tr("Open Changeset Manager"));
-            popupMenu.show(arrowButton);
+            if (changesetDialogAction != null) { // fix #15444
+                final OpenChangesetPopupMenu popupMenu = new OpenChangesetPopupMenu(changesetDialogAction.id);
+                popupMenu.insert(changesetDialogAction, 0);
+                ((AbstractButton) popupMenu.getComponent(0)).setText(tr("Open Changeset Manager"));
+                popupMenu.show(arrowButton);
+            }
         });
         changesetPanel.add(arrowButton, BorderLayout.EAST);