XML example not rendered with oneOf, anyOf

[ovtep]

• OS: Windows 10 Pro (64 bit)
• Browser: Chrome
• Version: 85.0.4183.121
• Method of installation: online swagger editor
• Swagger-UI version: online swagger editor
• Swagger/OpenAPI version: OpenAPI 3.0

Content & configuration

Example Swagger/OpenAPI definition:

openapi: 3.0.0
info:
  description: Test API
  version: v1
  title: Test API
tags:
  - name: Test
    description: Test API
servers:
  - url: /v1
paths:
  /test:
    post:
      tags:
        - Test
      summary: Test endpoint
      description: Test
      operationId: postTest
      responses:
        '200':
          description: Returns response
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/test'
            application/xml:
              schema:
                $ref: '#/components/schemas/test'
components:
  schemas:
    test:
      type: object
      properties:
        a: 
          type: string
        b:
          type: integer
        c:
          type: array
          items:
            $ref: '#/components/schemas/Things'
        d:
          type: array
          items:
            anyOf:
              - $ref: '#/components/schemas/TextObject'
              - $ref: '#/components/schemas/ImageObject'
            
            
    Things:
      type: object
      oneOf:
      - $ref: '#/components/schemas/TextObject'
      - $ref: '#/components/schemas/ImageObject'
            
    TextObject:
      required:
      - data
      type: object
      properties:
        objectType:
          type: string
          example: Text
          xml:
            name: ObjectType
        data:
          type: string
          example: This is a text
          xml:
            name: Data
      description: Contains a text      
      
    ImageObject:
      required:
      - data
      type: object
      properties:
        objectType:
          type: string
          example: image
          xml:
            name: ObjectType
        data:
          type: string
          example: This is a image
          xml:
            name: Data
      description: Contains a image

Describe the bug you're encountering

There is an issue with XML rendering when the open api schema contains oneOf, anyOf.

To reproduce...

Steps to reproduce the behavior:

1. Go to 'https://editor.swagger.io/'
2. Paste the Example Swagger/OpenAPI definition.
3. Go to response 200, select media type XML.
4. See that the schemas with oneOf and anyOf are not rendered.

Expected behavior

Rendering the equivalent XML. The XML shall be rendered as JSON does, containing every schema from oneOf, anyOf.

Additional context or thoughts

The issue is described differently in #4943
There is marked as enhancement. I think this is a bug.