private void validateTextFields(final int selectedIndex) {
    for (EditorTextField textField : myOldClassParameterNameFields.values()) {
      textField.setEnabled(true);
    }

    final Object variable = myVariables[selectedIndex];
    if (variable instanceof PsiField field) {
      final PsiClass hisClass = field.getContainingClass();
      final Set<PsiMember> members = myThisClassesMap.get(hisClass);
      if (members != null && members.size() == 1 && members.contains(field)) {  //Just the field is referenced
        myOldClassParameterNameFields.get(hisClass).setEnabled(false);
      }
    }
  }
private void validateTextFields(final int selectedIndex)