[bug]: [need clarification] Lost GraphQL type tag, unable to switch/view MyMutation

[wangzhou-ccc]

Describe the bug
After clicking the create graphql playground button, I enter the API URL normally to get the graphql schema.
Under Explorer, only query is visible, but I can't switch or view mutation. Seems to be lost.
No matter how I refresh/click, you will not be able to display My mutation.
But in the Documentation Explorer, I can see that the mutation is normal, meaning that the IntrospectionQuery API responds normally.
Hopefully the relevant authors can answer whether it is a setup problem or a valid bug. Thank you very much!
This software is very powerful and does a great job!

To Reproduce
As described, as screenshot.

Expected behavior
can switch or view mutation

Screenshots

Desktop (please complete the following information):

• OS: WIN 11

• Browser: Desktop software (the same goes for Google Chrome)
  

• Version v3.2.4
  

Additional context
Add any other context about the problem here.

[Nishchit14]

@wangzhou-ccc you need to keep at least one mutation query (even empty mutation) in the playground.

[wangzhou-ccc]

@Nishchit14 Well, after trying, it's been solved. Thank you for your answers!