1080p fullscreen not applied in CM

[YtseJammm]

I'm sorry if this has been answered already.
My desktop resolution is 4K, and I would like to start the game in 1080p fullscreen. When I checked fullscreen and choosed 1080p in CM video settings, the game started with 4K resolution automatically and UI was pretty small ,though I didn't check fix resolution automatically.
The only way of 1080p fullscreen for me is to uncheck fullscreen to start a windowed game and press alt+enter.
How can I start a 1080p game directly without pressing alt+enter?

Thanks.

 

[YtseJammm]

Alright, uninstall and reinstall the game, and everything works well.