thanks for your insight on the protocol. I'm looking into it now.

I created a table cell editor that extends JComboBox and implements
TableCellEditor. It's constructor installs my custom key selection
manager (I followed the JScrollBar sample from Chapter 15 of Eckstein,
Loy, and Wood) . I got what I wanted, but I don't know why. my
fireEditingStopped implementation is similar to
AbstractTableCellEditor's implementation. I guess I don't understand
the protocol these components use, but I am satisfied with how things
are going. Are you aware of any ramifications I should know about?

public class AshtonComboBoxTableCellEditor extends JComboBox
implements TableCellEditor {

   protected transient Vector listeners;
   protected transient Object origValue;

   public AshtonComboBoxTableCellEditor(Vector parts) {
       setKeySelectionManager(new AshtonComboBoxKeySM());
       listeners = new Vector();
       for (int i=0, n=parts.size(); i<n; i++)
           addItem(parts.get(i));
   }

   public Component getTableCellEditorComponent(JTable table, Object
value,
                                                boolean isSelected,
                                                int row, int column)
{
       if (value == null)
           return this;

       setSelectedItem(value);
       table.setRowSelectionInterval(row, row);
       table.setColumnSelectionInterval(column, column);
       origValue = getSelectedItem();

       return this;
   }

   public Object getCellEditorValue() {
       return getSelectedItem();
   }

   public boolean isCellEditable(EventObject anEvent) {
       return true;
   }

   public boolean shouldSelectCell(EventObject anEvent) {
       return true;
   }

   public boolean stopCellEditing() {
       fireEditingStopped();
       return true;
   }

   public void cancelCellEditing() {
       fireEditingCancelled();
   }

   public void addCellEditorListener(CellEditorListener l) {
       listeners.addElement(l);
   }

   public void removeCellEditorListener(CellEditorListener l) {
       listeners.removeElement(l);
   }

   protected void fireEditingCancelled() {
       setSelectedItem(origValue);
       ChangeEvent ce = new ChangeEvent(this);
       for (int i=listeners.size()-1; i>=0; i--)
           ((CellEditorListener)listeners.elementAt(i)).editingCanceled(ce);
   }

   protected void fireEditingStopped() {
       ChangeEvent ce = new ChangeEvent(this);
       for (int i=listeners.size()-1; i>=0; i--)
           ((CellEditorListener)listeners.elementAt(i)).editingStopped(ce);
   }