Cmd-Tab switcher on all screens

This week, on Monday gone in fact, we moved office. We've now got a bigger space and, as part of that, bigger desks. Somewhat (but not entirely) coincidentally the work desk will also convert into a standing desk¹. Also also... I inherited a second screen for the desk too. Ever since the days of CRTs and video cards that supported it, I've been a fan of having at least a couple of screens in front of me, and now at my work desk I've got 3 (two external displays and the display of the MacBook Pro itself).

This caused a slight problem though: horizontally there's quite the spread of things to look at. This is fine, mostly I'm looking at the screen that's in front of me; the MacBook is to the left and the "second" screen is to the right, both with "other" stuff on them. In front of me is Emacs and my browser, which I flip between lots.

The problem is this: the MacBook needs to go to the left (because of physical layout), which means that despite me setting the screen in front of me as the "main" screen, the Cmd-Tab display (you know the thing: when you hit Cmd-Tab you see the icons of all your active applications) appears on the left-most display, which is the MacBook.

Not great. If I'm looking at the right-most display, and want to switch using the keyboard, I've got to look over to the left, as a worst case. That makes for a lot of unnecessary head-swivelling.

One quick Google later and Today I Learnt that the following pretty much solves the problem:

$ defaults write com.apple.Dock appswitcher-all-displays -bool true
$ killall Dock

As the name of the setting would suggest: once done, the switcher appears on all displays.

That's perfect.