In a world with "Adventure", you cannot change player permissions

Summary:
In a world with "Adventure", you cannot change player permissions. And also set player permissions when connected.

Steps to Reproduce:

1. Change the game mode to Adventure.
2. Try changing player permissions (your permissions).

Observed Results:
Buttons for changing player permissions are gone.

Expected Results:
Player permissions can always be changed. For example, to issue an operator.

Image: