I too have the same issue, it's like Clocknova described, but it's not only the clicks that goes through the UI, mouse hovering also goes through, when I hover the mouse in the inventory things that are on the ground beneath the inventory screen trigger the hover dialog. What seems to be happening is that things that are on the foreground do not stop mouse events for things beneath. I must say that after a while it becomes SUPER annoying.
My specs:
macOS High Sierra 10.13.1
iMac (27-inch, 2017)
3,5 GHz Intel Core i5
24 GB 2400 MHz DDR4
Radeon Pro 575 4GB
