checkBox.setHorizontalAlignment(SwingConstants.CENTER);
component = checkBox;
} else if (element instanceof StringCriterionElement) {
StringCriterionElement stringElement = (StringCriterionElement) element;
boolean acceptRE = stringElement.acceptRegularExpression();
boolean acceptExp = stringElement.acceptPtolemyExpression();
Color background;
if (acceptRE) {
background = _REGULAR_EXPRESSION_BACKGROUND;
} else if (acceptExp) {
background = _PTOLEMY_EXPRESSION_BACKGROUND;