if (parameterKeyConstraint != null) {
param = new ConstrainedParameterWidget(parameterKeyConstraint, name, value);
} else {
param = new CustomParameterWidget(name, value);
}
param.addChangeHandler(new ChangeHandler() {
@Override
public void onChange(ChangeEvent arg0) {
Widget w = (Widget) param;
dataRequestParameters.remove(w);
}