FULL PRODUCT VERSION :
java version "1.6.0_01"
Java(TM) SE Runtime Environment (build 1.6.0_01-b06)
Java HotSpot(TM) Client VM (build 1.6.0_01-b06, mixed mode, sharing)

ADDITIONAL OS VERSION INFORMATION :
Microsoft Windows XP [Version 5.1.2600]

A DESCRIPTION OF THE PROBLEM :
If I have a JTable, and I set all the columns to use the DefaultCellEditor with the clickCountToStart set to 1 (it defaults to 2), the table works fine if placed on a panel directly within a JFrame. But if it is placed within a JInternalFrame, the focus is all messed up.

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
1. Run the test case
2. Click on the JTextField under Label "Field1".
3. Click inside a cell in the JTable below the JTextField.
4. Note that even DefaultCellEditor.setClickCountToStart(1) is used. 
5. Comment line 70 & uncomment line 71 in the test case
6. Repeat 2 & 3 to observe the difference.

REPRODUCIBILITY :
This bug can be reproduced always.

---------- BEGIN SOURCE ----------
import java.awt.Dimension;
import java.util.Enumeration;
import javax.swing.BoxLayout;
import javax.swing.DefaultCellEditor;
import javax.swing.JDesktopPane;
import javax.swing.JFrame;
import javax.swing.JInternalFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTable;
import javax.swing.JTextField;
import javax.swing.table.TableColumn;
import javax.swing.table.TableColumnModel;
 
public class TableTest extends JFrame
{
	
	public TableTest()
	{
		addWindowListener(new java.awt.event.WindowAdapter()
		{
			public void windowClosing(java.awt.event.WindowEvent evt)
			{
				System.exit(0);
			}
		});
		
		JPanel panel = new JPanel();
		panel.setLayout(new BoxLayout(panel, BoxLayout.Y_AXIS));
		
		String[] columnNames = {"First Name",	"Last Name","Sport","# of Years","Vegetarian"};
		Object[][] data= new Object[3][5];
		JTable table = new JTable(data, columnNames);
		table.setSurrendersFocusOnKeystroke(true);
		table.putClientProperty("terminateEditOnFocusLost", Boolean.TRUE);
		
		DefaultCellEditor editor = new DefaultCellEditor(new JTextField());
		
		// ************ change to 2 to make it work smoothly
		editor.setClickCountToStart(1);
		TableColumnModel tcm = table.getColumnModel();
		Enumeration e = tcm.getColumns();
		TableColumn col = null;
		while( e.hasMoreElements() )
		{
			col = (TableColumn) e.nextElement();
			col.setCellEditor(editor);
		}
		
		JScrollPane jScrollPane = new JScrollPane();
		jScrollPane.setViewportView(table);
		
		panel.add(new JLabel("Field 1"));
		panel.add(new JTextField(15));
		panel.add(jScrollPane);
		
		// ************ comment out one or the other of these to see error
		initInteralFrame(panel);
		//initNoInteralFrame(panel);
		
		Dimension screenSize = java.awt.Toolkit.getDefaultToolkit().getScreenSize();
		setSize(new Dimension(800, 600));
		setLocation((screenSize.width-800)/2,(screenSize.height-600)/2);
	}
	
	private void initInteralFrame(JPanel panel)
	{
		JInternalFrame jif = new JInternalFrame();
		JDesktopPane desktop = new JDesktopPane();
		jif.setVisible(true);
		desktop.add(jif);
		setContentPane(desktop);
		jif.add(panel);
		jif.pack();
	}
	
	private void initNoInteralFrame(JPanel panel)
	{
		getContentPane().add(panel);
	}
	
	/**
	 * @param args the command line arguments
	 */
	public static void main(String args[])
	{
		new TableTest().setVisible(true);
	}
	
}

---------- END SOURCE ----------