main.setCellHorizontalAlignment(listBox, VerticalPanel.ALIGN_CENTER);
main.setCellHeight(listBox, "120px");
final SimpleButton okButton = new SimpleButton("OK", new ClickHandler() {
public void onClick(ClickEvent event) {
dialog.hide();
int index = listBox.getSelectedIndex();
String coreName = listBox.getValue(index);
}
});
okButton.setEnabled(false);