Shaking screen using a dual screen

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https://bbs.archlinux.org – Hi there,After an update of my system, I've discovered a particular issue: when plugin a second screen via HDMI, my laptop screen display gets kind of shaking, like if the frequency rate was not well set. But this concerns only the laptop monitor, the secondary monitor isn't affected by this issue. After that, even unplugging the secondary monitor doesn't change anything, and the laptop's monitor keeps "shaking"; I need to reboot my system in order to get back a normal display... until the next I'm gonna use a secondary monitor ^^It looks like this issue is t (HowTos)