How to fix screen flickering on Ubuntu 16.04 when connecting a second monitor?

Question

linux

There is a laptop, the laptop has VGA. There is an old monik 19 "while there was Windows - I often used a second monitor to increase the productivity of absorbing content on YouTube, etc.
So I wanted to stick ubuntu, 16.04.XX, with all the latest updates. Shell - Unity.
Built-in Intel video on the laptop HD4000
The essence of the artifact - when you drag a window on a large monitor (as an option, enter - exit to full screen mode, or when a sound adjustment indicator bar appears), the monitor on the laptop starts flickering wildly until the special effect on the large monitor ends. Wildly annoying. Maybe something how do you need to tinker? :D
I'm not in a hurry to upgrade to ubuntu 18, there's a bugger there, I don't want to... the unit seemed more convenient.