Francisco -

>I'm a beginner in Squeak ( in Smalltalk too ) . The point is,  when I attempted to create a new class with the name #Link,  the system crashed. I have found later that this name is used for a class of Collections-Support, but the system doesn't warn me.
>Is this correct ?

Obviously not.

It IS the intention in Squeak to make it easy to make fundamental changes (and therefore to get in trouble), but it would be easy in your case to have warned you if your definition came from a browser in which the pre-existing definition was not visible.

(Someone else out there in Squeak-Land might supply just such a cautionary check if we close our eyes and wish real hard ;-)

	- Dan