Reference: Insert Server Lists
You delete a server list from the system using the Insert Server List dialog. A server list is deleted by first moving it to the Selected Server List window. This is accomplished by either double-clicking the item, or single clicking and using the Add button. Next, you select the item and click the Delete List(s) button.
Warning: This operation deletes the list from the system even when it is currently in use within other scripts as a dynamic server list.