Correct. It is the same on my machine.
Maybe it is interesting to note that an extension of any element except classes (and label files, but that's another story) is an element type in the AOT. For example you get Forms and Form Extensions. An extension of a class is still a class. Not Class Extension. Then again that is just how it is presented to us.
But the answer is still simple: If you want to extend a class - create a new class. It's like that everywhere and for everyone
