@Override
    public void visitReferenceExpression(@NotNull PsiReferenceExpression expression) {
      super.visitReferenceExpression(expression);
      final PsiElement referenceNameElement = expression.getReferenceNameElement();
      if (referenceNameElement ==  null) {
        return;
      }
      final String referenceName = expression.getReferenceName();
      final String className;
      String value;
      if ((value = gridbagConstants.get(referenceName)) != null) {
        className = checkExpression(expression, "java.awt.GridBagConstraints");
      } else if ((value = borderLayoutConstants.get(referenceName)) != null) {
        className = checkExpression(expression, "java.awt.BorderLayout", "java.awt.GridBagConstraints");
      } else if ((value = flowLayoutConstants.get(referenceName)) != null) {
        className = checkExpression(expression, "java.awt.FlowLayout");
      } else if ((value = scrollPaneConstants.get(referenceName)) != null) {
        className = checkExpression(expression, "javax.swing.ScrollPaneConstants");
      } else if ((value = boxLayoutConstants.get(referenceName)) != null) {
        className = checkExpression(expression, "javax.swing.BoxLayout");
      } else {
        return;
      }
      if (className == null) {
        return;
      }
      registerError(referenceNameElement, className, value);
    }
@Override
    public void visitReferenceExpression(@NotNull PsiReferenceExpression expression)