fullscreen display issues on secondary screen

Put the summary of the bug you're having here

What I expected to happen was...:
Minecraft would be able to fullscreen on my second (1080p) display under the "duplicate" or "second screen only projection settings on my laptop (4k display)

What actually happened was...:
It just shows up "fullscreened" in the upper left corner of the screen.

Steps to Reproduce:
1. Not sure really. I was spending a couple hours switching between projection settings, profile resolutions, and timing of plugging in/unplugging the hdmi cable. In this particular crash, I think I had it on second screen only, mini-fullscreened, and then tried to switch to duplicate.