Text Edit example doesn't always update the style combo box after deleting text

The Text Edit example doesn't always update the style combo box when we delete some text.

1. Insert some text in a new line before a heading.
2. Select the start of this line.
3. Delete the text using "Delete" in the keyboard. Do this until the heading that was in the next line comes to the current line.

When the heading comes under the cursor, the style combo box still indicates "Standard", instead of the expected "Heading".