How to use a 4K monitor together with others?

I try to make use of a 4k monitor (ASUS 28 inch) together with two others (1920 x 1200). Either I can see almost no menus on the 4K display or the other monitors display magnified images. All windows I drag from one monitor to the other are somewhat distorted. The worst effect is on Parallels with WIN 7. All icons are minimized.

Is there an acceptable way to use the stuff conveniently?