Enter key not working in JTextArea

I'm working on a Java Swing application. I have a JTextArea inside a JScrollPane inside a JTabbedPane inside a JPanel. I can type in the JTextArea, and every key on my keyboard has the desired effect, except the enter key.

Tabs and spaces work fine. When I press the enter key, then type to the end of the line with word wrap enabled, the line is broken where I typed the enter key, leading me to believe that the issue is with how the JTextArea is displaying the text. I'm giving the JTextArea a new HTMLDocument. Note that when I do not give the JTextArea a new HTMLDocument, the enter key works perfectly well.

Simple code reproducing the problem:

import javax.swing.*;
import javax.swing.text.html.HTMLDocument;
import java.awt.*;

public class Driver extends JFrame {
    public Driver() {
        setLayout( new GridLayout( 1, 1 ) );

        JTabbedPane tabbedPane = new JTabbedPane();
        add( tabbedPane );

        JTextArea textArea = new JTextArea( new HTMLDocument() );
        textArea.setLineWrap( true );

        JScrollPane scrollPane = new JScrollPane( textArea );
        tabbedPane.addTab( "No enter key!", scrollPane );

        pack();
        getContentPane().setVisible( true );
        setDefaultCloseOperation( WindowConstants.EXIT_ON_CLOSE );
        setSize( 640, 480 );
        setVisible( true );
        setFocusable( true );
    }

    public static void main( String[] args ) {
        new Driver();
    }
}