Has anyone got the multiport adaptor on hand and can confirm for sure that it can extend to an external monitor (i want both the rMB and the ext. monitor on, not just the ext. one).? On apple.com it did not state that it can extend: "this adapter allows you to mirror your MacBook display to your HDMI-enabled TV or display in up to 1080p at 60Hz or UHD (3840x2160) at 30Hz. It also outputs video content like movies and captured video. " Other old displayport adaptors clearly state it can BOTH mirror and extend. 1. I searched here and no old threads for this question. 2. Called apple and no one knows. 3. Visited an apple store and its out of stock so no one knows and can't try it out. Very frustrating if the adaptor can EXTEND but apple makes a mistake of not stating it clearly on their website..... And more frustrating if the $79 thingy that probably costed $8 to make cannot extend.