Cannot use screen capture apps in Wayland

I have Ubuntu 18.04 (updated from 17.10 where I had the same problem), and when I use it with Wayland, I cannot use any screen capturing/recording apps. For instance, when I try to take a screenshot with Shutter, I get a weird pattern instead of what's actually on my screen:

I know I can just switch to GNOME/Ubuntu on Xorg, but sometimes that's not an option. Is there a fix for this? Or a certain app that works as it should on Wayland?

The default Screenshot (gnome-screenshot) application should work fine. Search for it in the "Activities" overview or use the Prt Sc key. You can capture your whole screen just by running

gnome-screenshot

For the GUI, run

gnome-screenshot -i

Run

gnome-screenshot -h

to see all possible options.