How to prevent sessionStorage being inherited when using target="_blank"/window.open() to open a new window/tab?

According to the Webstorage Specification, "When a new Document is created in a browsing context which has a top-level browsing context, the user agent must check to see if that top-level browsing context has a session storage area for that document's origin. If it does, then that is the Document's assigned session storage area."

So, my take on this is that if you close the tab, then open a new tab, it will be a new "session" per the specification. However, if the tab remains open and you then open a new tab, the top-level browsing context matches, so the sessionStorage is referenced.