I've got MacBook Pro with macOS Mojave 10.14.6 and an external monitor connected through "j5create JDC 381" USB-C to HDMI adapter.
Weird thing sometimes happens when using Chrome - when it's on the external screen it sometimes stops responding. I have to kill it through Activity Monitor BUT the window stays displayed even after the process is killed. It completely makes the monitor unusable and I can't do anything about it - I tried unplugging the HDMI adapter, power off/on the monitor, switch display mode to mirror and back, etc. Only reboot helps.
Any ideas how to "unblock" the external screen without reboot when something like this happens?