So, I'm not sure if the fix for this lies with Microsoft, Intel's graphics, or the makers of the MST hubs, but it's very frustrating that we can't use dual external monitors with the Surface dock without a menagerie of workarounds and hubs. Every other business-grade laptop dock supports dual external monitors out of the box (well, at least Dell, which is what we used before this).
TL;DR - Try an EVGA 200-****-1301-L2 hub.
So here's my experience.
I purchased a Surface Pro 3 (i7/512GB) to replace my main workstation (I code). Since my existing monitors were of the Korean type (Yamanashi 30") I had to either purchase two active DisplayPort to DualLink DVI adapters for around a hundred bucks each, OR, replace the monitors for something with native ****.
I choose the second option. However, due to my criteria for monitors I couldn't get anything which supported daisy-chaining out of the box. I ended up grabbing a couple Benq BL3200PT monitors and after a little searching around on forums a StarTech MSTMDP123DP MST hub.
My god what a f$%#ing nightmare that turned out to be. From the outset I had nothing but problems with screens flickering, disconnecting and reconnecting by themselves and last but by no means least BSoDs.
I kept trying to get this setup working for about a month, but finally gave in and returned the StarTech to Amazon for a refund.
I then purchased a couple no-name MiniDP-**** cables and ran docking-station to one monitor and SP3 to the other. I continued this until it became a chore having to reconnect cables every time I re-docked my SP3.
At this point I considered getting rid of the SP3 completely and going back to my old rig still sitting idle under my desk, but stubborn as I am I figured I'd give it one more chance. I took the plunge on a EVGA 200-****-1301-L2 MST hub. As soon as I plugged this in, still using the no-name mDP-**** cable connected to my docking station my SP3 recognized both external monitors and I was able to extend my desktop no problem.
So, basically, if you're all still having issues, try replacing your existing hub with the EVGA one (apparently there are chipset differences between the L2 and non L2 versions so get the L2) and it should work out of the box.
Thanks to all. You saved my life.
With powerpoint, going in presentation mode and going back to edit mode put the surface 3 in external screen even if there is no!
Windows+P helped me go back to the S3 screen.
Very good device but so messy in some occasion....