If this comment is to be believed, it's not Apple's fault. It's the apps mucking around with the internals of AppKit.
This example just happens to illustrate two of my least favorite software engineering practices: (1) despite one piece of code making a method private, another piece of code still overrides it/modifies it/calls it, an affront to the idea of encapsulation; (2) a piece of code has different behavior depending on the identity of a function, contrary to the principle of extensionality.
If this comment is to be believed, it's not Apple's fault. It's the apps mucking around with the internals of AppKit.
This example just happens to illustrate two of my least favorite software engineering practices: (1) despite one piece of code making a method private, another piece of code still overrides it/modifies it/calls it, an affront to the idea of encapsulation; (2) a piece of code has different behavior depending on the identity of a function, contrary to the principle of extensionality.