Applying display configuration does not work on ultrawide monitor

When I setup my display configuration, the switchboard plugin just doens't do anything and running it trough the commandline gives a lot of errors.

Youtube video describing the problem:
https://www.youtube.com/watch?v=AvluX7DcE4A

Full error traceback:
http://pastebin.com/9BpDzePe

System info:

jeroen@Jeroen-PC:~$ uname -a
Linux Jeroen-PC 4.4.0-47-generic #68-Ubuntu SMP Wed Oct 26 19:39:52 UTC 2016 x86_64 x86_64 x86_64 GNU/Linux

Nvidia driver:
proprietary 375.20 nvidia driver

Displays:
1 3440x1440 trough displayport and 1 1920x1080 with HDMI

Launchpad Details: [#LP1645417](https://bugs.launchpad.net/bugs/1645417) Jeroen - 2016-11-28 18:05:25 +0000

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