Chrome Version: 54.0.2840.101
Chrome OS Version: 8743.85.0 (Official Build) stable-channel veyron_jaq
Chrome OS Platform: Medion AKOYA S2013

Please specify Cr-* of the system to which this bug/feature applies (add
the label below).

Steps To Reproduce:
(1) Connect the docking station *Dell D3000 USB 3.0 Dock* over the right USB port.
(2) Connect the monitor Dell UP3214Q (maximum 3840x2160) over HDMI to the docking station.
(3) Choose to extend the screen.
(4) The screen of the external monitor is put right of the laptop monitor.
(5) The image on the external monitor has visible compression artifacts.

Expected Result:

Everything should be visible on the external screen.

Actual Result:

The screen is rendered too big on the external monitor and extends the boundaries. Sometimes the mouse cannot be seen, and opening a browser window the top part with the address/location bar cannot be seen.

How frequently does this problem reproduce? (Always, sometimes, hard to
reproduce?)

Always.

What is the impact to the user, and is there a workaround? If so, what is
it?

Operating the device gets very hard.

Please provide any additional information below. Attach a screen shot or
log if possible.

Please tell me what you need. Once the guessed session also crashed for example.