I've had this same problem for some time now. Used to be able to play in 1366x789 but suddenly was no longer able to play in full screen. Been able to fix it today, so hopefully this will
In my case it was caused by having an old graphics card + windows 10 and not being able to select 1366x789 resolution in my display settings. Tried reinstalling my graphics drivers, but it didn't work. Then found this post in which they suggested to install CRU and manually add the 1366x789 resolution. Followed the steps and voilá, now it works! Hope it helps for you too.
