Index: trunk/src/org/openstreetmap/josm/gui/dialogs/changeset/ChangesetDiscussionPanel.java
===================================================================
--- trunk/src/org/openstreetmap/josm/gui/dialogs/changeset/ChangesetDiscussionPanel.java	(revision 17369)
+++ trunk/src/org/openstreetmap/josm/gui/dialogs/changeset/ChangesetDiscussionPanel.java	(revision 17370)
@@ -117,5 +117,6 @@
         JPanel pnl = new JPanel(new BorderLayout());
         table = new JTable(model, new ChangesetDiscussionTableColumnModel());
-        table.setAutoCreateRowSorter(true);
+        table.setRowSorter(new ChangesetDiscussionTableRowSorter(model));
+
         table.getColumnModel().getColumn(2).addPropertyChangeListener(evt -> {
             if ("width".equals(evt.getPropertyName())) {
Index: trunk/src/org/openstreetmap/josm/gui/dialogs/changeset/ChangesetDiscussionTableRowSorter.java
===================================================================
--- trunk/src/org/openstreetmap/josm/gui/dialogs/changeset/ChangesetDiscussionTableRowSorter.java	(revision 17370)
+++ trunk/src/org/openstreetmap/josm/gui/dialogs/changeset/ChangesetDiscussionTableRowSorter.java	(revision 17370)
@@ -0,0 +1,20 @@
+// License: GPL. For details, see LICENSE file.
+package org.openstreetmap.josm.gui.dialogs.changeset;
+
+import java.util.Comparator;
+
+import javax.swing.table.TableRowSorter;
+
+/**
+ * The row sorter for the changeset discussion
+ * @since 17370
+ */
+class ChangesetDiscussionTableRowSorter extends TableRowSorter<ChangesetDiscussionTableModel> {
+
+    ChangesetDiscussionTableRowSorter(ChangesetDiscussionTableModel model) {
+        super(model);
+
+        // column 0 - Date
+        setComparator(0, Comparator.naturalOrder());
+    }
+}