A JComboBox using the DefaultCellEditor (in a JTable) shows the following
problems:

1. Pressing ESC while the drop down list is displayed removes the list
   but does not cancel the JTextField editor.

2. If you modify the value in the text field, the only way to accept
   the change is to press return. If you click on another cell in the table
   the change is lost.

Reproduced with Java 1.3.0-C on Solaris using TableExample4 in the Swing 1.1
examples (change the combobox to be editable).