Posted on June 29 2017 and helped to solve issues of getting DCS to display full screen on new samsung 49 in monitor.
Thanks for the INFO...Search and find was easy and the resolution was quick.
Go to C:\Users\[your user profile]\Saved Games\DCS.Openalpha\Config and delete options.lua file. That will revert all settings (apart from controller ones) to default.
Remember two things: a) this Saved Games\DCS[...] location stores all your personal data and settings for DCS; b) installing/uninstalling/repairing the game does not touch that folder at all, so it anything's messed up over there, it's going to stay messed up until you go there and delete that folder manually yourself.