Recently, I installed Ubuntu 15.04 on my machine and got everything running about as it should, except for one thing: my external monitor can not be set as default.
Every time I plug in my external monitor, the screen extends how it's supposed to. However, when I attempt to set it as my default monitor, LightDM immediately goes into a loop where the screen goes off for about a second, and flashes on for a very brief interval.
Additionally, this problem happens if I end LightDM (service
or other method) and re-launch it. I can enter my password, but then this same flashing happens.
However, this does not happen when I first boot up my machine.
How can I fix this issue?
Ubuntu 15.04, Intel HD 4400, NVIDIA GT745M (driver 352.14), Bumblebee
Running Cinnamon + Docky