The documentation of onClose wrongly refers to Menu.opened. It should refer to Menu.closed

It's currently

Returns a callback, if any, to be invoked if the platform menu receives a "Menu.opened" method call from the platform for this item.

but it should be

Returns a callback, if any, to be invoked if the platform menu receives a "Menu.closed" method call from the platform for this item.

The documentation of onOpen has a grammar issue.

It's currently

Only items that have submenus will have this callback invokes

but it should be

Only items that have submenus will have this callback invoked.