Display connected to Dell U2414H on DisplayPort Out does only show cloned desktop / How to enable DisplayPort MST on U2414H / Three independent displays with Dell XPS12 with DaisyChain

I got a new Dell U2414H monitor. The plan was, to connect it to my Dell XPS 12 tablet with DisplayPort and connect my Dell U2412M to the DisplyPort out to get 3 independent displays working.
Setting everything in the first place only gave me a cloned desktop of the U2414H on the U2412M. Also my display settings on XPS 12 only showed me two displays instead of three.

How-I-fixed-it:
The problem was, that by default, DisplayPort 1.2 on the U2414H is DISABLED!
To get DisplayPort DaisyChain working, it has to be enabled manually in the monitor setup, as described in the user manual:
ftp://ftp.dell.com/Manuals/all-products/esuprt_display_projector/esuprt_Display/dell-u2414h_User%27s%20Guide_en-us.pdf#page=25

This is necessary to make the graphics card detect them as separate displays (they can even have different resolutions!).

The next step is, to enable three independen displays in the XPS 12 Intel HD 4000 settings, as descibed on the Intel FAQ "Configuration 3-Displays FAQ":
http://www.intel.com/support/graphics/sb/cs-033714.htm