Some pieces of text on the screen are shown at exaggerated font sizes, for example:
ReFH does not natively support the latest hi-dpi devices, such as touch-screen laptops that with a 3,200 x 1,800 pixel density. Microsoft does, however, provide a number of compatibility fixes in Windows 10 that can be used to compensate.
Right-click on the icon used to launch ReFH (from the list of applications shown in Windows 10 when you press the Windows key -> FEH Software -> ReFH2). Select More -> Open File Location:
Right click on the ReFH2 shortcut, then Change High DPI settings, and try the various High DPI scaling override options: