When you add/edit a module, in some configurations, an "add group/grouping access restriction" button in "common module settings" section is displayed as disabled, but can't, in any way, be active.

1. find a module that allow groupings but not groups (or edit an existing module like mod_choice and edit mod/choice/lib.php and change in choice_supports() function this line : case FEATURE_GROUPS: return false;)
2. add a new instance of this module in your course

actual result :

1. in "common module settings" section, you should have a disabled button named "add group/grouping access restriction"

expected result :

1. in "common module settings" section, you should not have a disabled button named "add group/grouping access restriction"