I have ubuntu 16.04, and 4k monitor for this system, in unity tweak tool I've added font sizes to all fields (13 size) and added zoom ratio in appearance settings to 1.75 All icons, browser, etc looks fine.
But today something went wrong, and icons and fonts in default file manager decreased dramatically. No changes and ratios in tweak tool doesnt work.
Menu on right mouse click is also decreased in default manager and desktop. Another manager has normal sizes, but i can't understand how to fix those fonts and icons.