[Request] for renaming variables

[Angus]

I refer to Joe Horn's post

Quote:All are legal, and all retain their values (and names!) in both modes, with the first three remaining Home vars, and the other three remaining CAS vars, as can be seen by pressing the Vars key, or via the Memory Manager.

Doesn't that mean, that if I define a variable X in the cas it does NOT coexist with a home variable X??? So a single letter variable in capital letter refers to the home variable, althogh it it used/created in the cas?
Man I thought I got it....