Add new Stylesheet inside detached Stylehseet

When we open stylesheet in a new tab we can't access stylesheet tab inside Oxygen builder. It took us to detached stylesheet. But If we want to add a new stylesheet we have to add it inside builder. So if we open our stylehseet in new tab we have to close it to add a new stylehseet. It world be great we have a option to add a new stylesheet inside detached stylesheet tab