ellipsisButton.setMargin(new Insets(0, 0, 0, 0));
ellipsisButton.addActionListener(new ExtendedEditorAction());
final DefaultComboBoxModel model =
new DefaultComboBoxModel(ExpressionUtil.getInstance().getKnownExpressions());
model.insertElementAt(null, 0);
expressionEditor = new JComboBox(model);
expressionEditor.setEditable(true);
expressionEditor.setRenderer(new ExpressionListCellRenderer());
expressionEditor.setEditor(new ExpressionComboBoxEditor(true));
expressionEditor.getInputMap().put(UtilMessages.getInstance().getOptionalKeyStroke