U2718Q, Latitude E7470, cannot connect to PR02X E-Port Plus dock

cannot? why not?

@sunnyvally  when asking about technical issues, it generally helps to provide technical information.  For example:

- What exactly happens when you connect the display?  Just basically saying "it doesn't work" doesn't really help anyone help you.

- Have you updated your Latitude E7470 BIOS and GPU drivers?

- Do other devices attached to the dock work properly with this system?

- Do other displays work properly through the dock if you have one to test?

- Do you have any other displays attached at the same time as the U2718Q?  If so, does the U2718Q work when you don't have another display connected?

The U2718Q is a 4K 60Hz display, which means that if you're using a system that only has an Intel GPU, you would only be able to run that display on its own, not dual displays.  If you're using a system that has a discrete GPU, you would be able to run up to two 4K 60Hz displays simultaneously.  In addition, you need to make sure you have the second generation version of the E-Port dock that supports DisplayPort 1.2 and also USB 3.0.  The original version of the E-Port docks only run DisplayPort 1.1, which won't support 4K 60Hz displays.  The way to tell which generation you have is to check the rear USB ports.  If they're blue, then you have the second generation that supports USB 3.0 and DisplayPort 1.2.  If they're black, then you have a first generation dock.  The USB ports on the left side will always be black and always USB 2.0, fyi.