Can't enter the couponcode field anymore since update WordPress

Hello,

I have a problem, since I updated WordPress this week to the lastest version which was recommended I can’t enter the couponcode field anymore at coupons. The menu ”Listing options” can’t even extend anymore, so I can’t enter any new codes anymore which is frustrating. Here you can see the issue; https://postimg.org/image/gwhbgqr83/

Never seen this problem before, anyone have an idea to fix this issue/bug?

Hopefully someone can help me out.