Java SE (Java Platform, Standard Edition)

Hello, if the text in the JTextField is not the default size, it appears that the field does not resize properly. Here is an example: on the left is the field with default size (height 12 for my look and feel - metal on XP) "80", and on the right, the same with size 11. If you click in between 8 and 0 and delete the 0 and insert something in its place, the 8 will move a little out of the field and it will look like a "3" - only in the field with non-default size though (and it is smaller too, which should make it "easier" to enclose).

How can I have smaller size and still resize properly?? Here is the code - isolated to the minimum possible, compiles and runs

import javax.swing.*;
import javax.swing.event.*;

public class Foobar
{
	public static void main(String[] args)
	{
		JFrame frame = new JFrame();
		JPanel panel = new JPanel();
		frame.setContentPane(panel);
		FoobarTxtField normal = new FoobarTxtField("80");
		panel.add(normal);
		FoobarTxtField small = new FoobarTxtField("80");
		small.setFont(small.getFont().deriveFont((float)11));
		panel.add(small);
		frame.pack();
		frame.setVisible(true);
	}
}

class FoobarTxtField extends JTextField implements DocumentListener
{

	FoobarTxtField(String s)
	{
		super(s);
		getDocument().addDocumentListener(this);
	}

	public void insertUpdate(DocumentEvent e)
	{
		SwingUtilities.getRootPane(this).revalidate();
	}

	public void removeUpdate(DocumentEvent e)
	{
	}
	public void changedUpdate(DocumentEvent e)
	{
	}
}