The property questionStartIndex of survey doesn't work

[OlgaLarina]

@OlgaLarina Please use
"showQuestionNumbers": "on". It was the default value in V1.

const json = {
  questionTitleTemplate: "{no}) {title} {require}:",
  questionStartIndex: "A",
  requiredText: "(*)",
  pages: [
    {
      title: "This is the page {pageno} of {pagecount}.",
      questions: [
        {
          type: "text",
          name: "name",
          title: "Please type your name",
          isRequired: true
        },
        {
          type: "text",
          name: "email",
          title: "Please type your e-mail",
          isRequired: true,
          validators: [{ type: "email" }]
        }
      ]
    },
    {
      title: "This is the page {pageno} of {pagecount}.",
      questions: [
        {
          type: "comment",
          name: "comment",
          title: "{name}, please tell us what is on your mind"
        }
      ]
    }
  ],
  completedHtml:
    "<p><h4>Thank you for sharing this information with us.</h4></p><p>Your name is: <b>{name}</b></p><p>Your email is: <b>{email}</b></p><p>This is what is on your mind:</p><p>{comment}</p>"
};