Seems this issue has yet to be fixed on the latest V 220.127.116.110.
I am using a 4k screen on a 13' laptop. Windows 10 scales the layout to 200% by default, making everything look great. Well... almost everything.
Most functions and buttons are scaled on Maxthon, but I have found out that the Snap tool's icons don't scale. They look tiny on my screen and I have to stick my nose almost to the screen to read them. See the attachment
Buttons not scaling was an issue not uncommon back in the day when 4K screens were catching on, but now most programs have fixed their issues and improved their compatibility with 4k screens and Windows scaling function. I hope Maxthon will fix this issue soon too.