final FieldGroup fg = new FieldGroup("Account Interface Option");
fg.addField(FieldFactory.fcheckbox("subscribed", "subscribed", "Subscribed?", "Subscribed?"));
fg.addField(FieldFactory.ftext("setUpPrice", "setUpPrice", "Set Up Price", "Set Up Price", 8));
fg.addField(FieldFactory.ftext("monthlyPrice", "monthlyPrice", "Monthly Price", "Monthly Price", 8));
fg.addField(FieldFactory.ftext("annualPrice", "annualPrice", "Annual Price", "Annual Price", 8));
fg.addField(paramsPanel.getFieldGroup());
((IFieldWidget<Boolean>) fg.getFieldWidget("subscribed"))
.addValueChangeHandler(new ValueChangeHandler<Boolean>() {
public void onValueChange(ValueChangeEvent<Boolean> event) {