I have been unable to enter full screen mode as well - but I am on a single display so I am not sure if MC-5520 applies.
I filled out my own bug report https://bugs.mojang.com/browse/MC-5520 but it was automatically tagged as a duplicate to MC-297 "Pixel Format not Accelerated" (which it is NOT a duplicate of)...
I downloaded Display Driver Uninstaller from Guru3D website and completely blew away my nVidia drivers in Safe Mode. I then installed the drivers from nVidia's website. I am STILL getting the same issue.
Again - not sure if it is the same bug as MC-5520 or not - but it does sound like the same errors.
Made some progress. I am on a 4K monitor. I was getting the error while at 1920x1080. If I change my resolution to the recommended resolution of 3840 x 2160 - the game works fine and I can switch between full screen and back without issues. I tried 2560 x 1440 and got the same issue... so it seems to be the same resolution.
UPDATE - seems to be related specifically to the hertz of the resolution. 3840 x 2160 is at 30hz .. the other resolutions are at 59hz .. (Standard PnP Monitor Driver). If I force the hertz to 60hz (thereby resetting resolution to 640x480) it works fine..
*FIXED!*
Finally! In windows, I went into Display Settings, then Advanced display settings, then Display adapter properties at the bottom (under Related settings). I then clicked on the List All Modes button. From there I was able to list all resolutions:
By default it always went to 59 hertz - but I double clicked on the 60 Hertz line, then clicked Apply in the adapter properties window - tried it and it worked. Yay.