low res image while using Color section in Davinci Resolve 1

Hi everybody, i need help with an issue with Davinci Resolve 12:

When i work in Color section in Davinci resolve i find the image of the video very pixelated and apparently in low resolution (it's even more evident when i use the fullscreen) as you can see in the attached photo. The file i'm using is in Prores HQ and the native resolution is 1920x1080. In fact when i play the video using quicktime it has no problems and the shape and the resolution of the image are fine. Is it normal that while i am using Davinci Resolve it does that? if not what can i do to fix that?

Thank you for your help