Index: trunk/test/unit/org/openstreetmap/josm/gui/dialogs/NotesDialogTest.java
===================================================================
--- trunk/test/unit/org/openstreetmap/josm/gui/dialogs/NotesDialogTest.java	(revision 17269)
+++ trunk/test/unit/org/openstreetmap/josm/gui/dialogs/NotesDialogTest.java	(revision 17269)
@@ -0,0 +1,42 @@
+// License: GPL. For details, see LICENSE file.
+package org.openstreetmap.josm.gui.dialogs;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.util.Date;
+
+import javax.swing.JLabel;
+import javax.swing.JList;
+
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.RegisterExtension;
+import org.openstreetmap.josm.data.coor.LatLon;
+import org.openstreetmap.josm.data.notes.Note;
+import org.openstreetmap.josm.data.notes.NoteComment;
+import org.openstreetmap.josm.data.osm.User;
+import org.openstreetmap.josm.gui.dialogs.NotesDialog.NoteRenderer;
+import org.openstreetmap.josm.testutils.JOSMTestRules;
+
+import edu.umd.cs.findbugs.annotations.SuppressFBWarnings;
+
+/**
+ * Unit tests of {@link NotesDialog}
+ */
+class NotesDialogTest {
+
+    /**
+     * Setup tests
+     */
+    @RegisterExtension
+    @SuppressFBWarnings(value = "URF_UNREAD_PUBLIC_OR_PROTECTED_FIELD")
+    public JOSMTestRules josmTestRules = new JOSMTestRules().preferences();
+
+    @Test
+    void testMultiLineNoteRendering() {
+        Note note = new Note(LatLon.ZERO);
+        note.setCreatedAt(new Date());
+        note.addComment(new NoteComment(new Date(), User.createLocalUser(null), "foo\nbar\n\nbaz:\nfoo", null, false));
+        assertEquals("0: foo; bar; baz: foo",
+                ((JLabel) new NoteRenderer().getListCellRendererComponent(new JList<>(), note, 0, false, false)).getText());
+    }
+}