Displayed example not updated sometimes when switching between media types #5460

This issue is related to OAS3 examples support.

Q&A (please complete the following information)

• OS: Windows 10
• Browser: any
• Method of installation: https://editor.swagger.io
• Swagger-UI version: 3.23.0
• Swagger/OpenAPI version: OpenAPI 3.0

Content & configuration

Example Swagger/OpenAPI definition:

openapi: 3.0.2
info:
  title: test
  version: 0.0.0
paths:
  /foo:
    post:
      requestBody:
        description: A JSON object, XML object, or text string containing foo data
        required: true
        content:
          application/json:
            schema:
              type: object
            examples:
              foo_json:
                value:
                  foo: bar
              bar_json:
                value:
                  bar: foo
          text/plain:
            schema:
              type: string
              example: Hello, world!
          application/xml:
            schema:
              type: object
            examples:
              foo_xml:
                value: <foo>bar</foo>
              bar_xml:
                value: <bar>foo</bar>
      responses:
        201:
          description: Created

Describe the bug you're encountering

In certain cases, switching between media types does not update the displayed "Example Value".

Steps to reproduce

1. Go to https://editor.swagger.io and paste the spec above.
2. Expand the operation.
3. From the "Examples" list, select "bar_json".
4. From the media types list, select "application/xml".
   => The "Examples" list is updated to contain "foo_xml" and "bar_xml" but the displayed "Example Value" is not updated.
5. From the media types list, select "text/plain".
   => "Example Value" still contains the JSON example. Should display "Hello, world!".

Screenshots

Screenshot for step 4: