Low resolution, highly pixellated

I just installed Scrivener on my windows laptop. My attached monitor is 3840 x 2160. All fonts and graphics in Scrivener are low-resolution (highly pixellated) - it looks like I’m running software from 1990. I have attached a screenshot. It looks the same whether I view it on the monitor or on my laptop display.

I have searched the fora and FAQ but can’t find any mention of this problem.

Any advice?