diff --git a/examples/editor-libcosmic/src/main.rs b/examples/editor-libcosmic/src/main.rs
index 4222359..974e97f 100644
--- a/examples/editor-libcosmic/src/main.rs
+++ b/examples/editor-libcosmic/src/main.rs
@@ -333,9 +333,11 @@ fn update_alignment<'a, T: Edit<'a>>(editor: &mut T, align: Align) {
             std::cmp::Ordering::Less => (select.line, current_line),
             std::cmp::Ordering::Equal => (current_line, current_line),
         };
-        for line in editor.buffer_mut().lines[start..=end].iter_mut() {
-            line.set_align(Some(align));
-        }
+        editor.buffer_mut().lines.get_mut(start..=end).map(|lines| {
+            for line in lines.iter_mut() {
+                line.set_align(Some(align));
+            }
+        });
     } else if let Some(line) = editor.buffer_mut().lines.get_mut(current_line) {
         line.set_align(Some(align));
     }