if (filterCombo.getEditor().getEditorComponent() instanceof JTextField) {
String comboToolTipText =
"Enter an expression, press enter to add to list";
filterText = (JTextField) filterCombo.getEditor().getEditorComponent();
filterText.setToolTipText(comboToolTipText);
filterText.addKeyListener(
new ExpressionRuleContext(filterModel, filterText));
filterText.getDocument().addDocumentListener(
new DelayedFilterTextDocumentListener(filterText));
filterCombo.setEditable(true);
filterCombo.addActionListener(