Twitch Quality Lock by albert007

Twitch automatically lowers your stream's video quality whenever its tab isn't in the foreground — for instance when you pop the video out with Picture-in-Picture or switch to another tab — and only restores it when you switch back. This extension stops the Twitch player from noticing its tab is in the background, so it holds the quality you selected no matter which tab you're viewing. It runs only on twitch.tv, needs no setup, requests no special permissions, and collects no data.

Please review if it helps you so it can reach more people!!