How do I hide the keyboard viewer in macOS Mojave?

I turned on the Keyboard Viewer in my Mac Mini 2014 w/Mojave and I can't get it to go away. How do I get rid of it?

This is what showed up when I clicked the "Show Keyboard Viewer". Clicking the red dot at the top-left corner hides it, but when I hit anything on the keyboard, it reappears.

This window is being controlled by a Screen Share from another Mac Mini. When I switch to it in the monitor and use a mouse to close it, then return to the shared host, it comes right back when I hit a key.

[Re-Titled by Moderator]