Having trouble defining scopes from other ones with special characters

I am trying to define a scope based on another one, using the scope language syntax reference here : https://www.jetbrains.com/help/idea/scope-language-syntax-reference.html 

In this page I see that other scopes must be refered to using a $, with this example : $Scope1||$Scope2.
However this doesn't work when the name of the scope contains a special character like a space or a hyphen.

How can I refer to scope named "My Scope" for example, or "My-Scope" ? Any space or hyphen will give an error (unexpected character). Surrounding the name with " ", ' ', ( ), { } or [ ] also make them unexpected characters.

If my scopes shouldn't contain such characters, then how should I refer to default scopes like "Project Source Files" ?