How to automatically close an NSPopover in NSStatusBar on Exposé/Mission Control

Question

For other applications, like Dropbox and 1Password, the popover that opens when you click the NSStatusItem in the top bar automatically hides (and then reshows) if you open up Exposé/Mission Control with F3 to switch spaces.

How is this accomplished? I can't figure out a good way to listen for the F3 event like you can for left/right click, and 1Password works despite having Accessibility access enabled for something like this.

Thoughts?

Answer 1

This isn't a great answer, but I ended up abandoning NSPopover. NSWindow has an attribute 'collectionBehavior', which controls how the NSWindow behaves with respect to other spaces and Exposé. The behavior that I wanted (and that I noticed in 1Password and Dropbox) can be replicated with window.collectionBehavior = [.transient, .ignoresCycle]. .transient makes it so that when you open Exposé the window automatically hides, and re-opens when you close it, and .ignoresCycle makes it not behave like a real window when toggling through windows. I then just present it when the NSStatusBar item is toggled, and hide it otherwise.