Slack's new UI hits pretty different. Since it's rolling out slowly, being in multiple organisations where is really jarring as it impacts organisation-switching the most.
Next, open the inspector. It should now appear under "View" -> "Developer" -> "Toggle DevTools". Or if you're used to a Google-Chrome-like browser, do whatever you normally do to open the inspector (Cmd+Shift+I on a Mac).
Open the inspector, and execute this code in the console: (Or, have a read of what it's doing, at the bottom of this post first!)
Open the inspector, and execute this code in the console: (Or, have a read of what it's doing, at the bottom of this post first!)
Why do we have to repeat this per-organisation? Well: Slack keeps one of these configurations for every organisation you're in, as localStorage is scoped to a browser origin, and each Slack organisation is a different browser origin.