After the Discovery update the Resolution Scale slider in the Display settings are broken. If you set it to a value, for example it's default value of 1.0 it will revert to 0 the moment the game is closed.
The slider does not seem to do anything other than that, for example.. When you log in the slider will be set at 0, but the game is actually running at 1.0, the proper render scale.
The slider is simply broken. I decided to tag you @chrian#9670
because I feel bad for always bugging EngineerB4. Hehe.