Alpha Client In-Game Problems.

When the Alpha beta client came out, I tried it out right away. Everything looked cool but when it came to the in-game part, my screen would just randomly black out then to the game, out then in-game since I was playing fullscreen. To fix this, I had to play windowless or borderless for it to stop but I don't really like either one. Ever since then, I've been playing on the legacy client Does anyone know how to fix? (https://vimeo.com/197740631)