Allow an NSWindow (NSPanel) to float above full screen apps

Question

I'm trying to add a little window that provides "quick input" from any place in the system to the main app.

The user could hit a hotkey, the window pops up, and floats above all other windows.

For the most part, this isn't much of a problem. I can configure an NSWindow to be:

level = Int(CGWindowLevelKey.TornOffMenuWindowLevelKey.rawValue)
collectionBehavior = .CanJoinAllSpaces

I can also make it an NSPanel with NSNonactivatingPanelMask option set.

The only problem is: how can I make it so that the window can pop up on the screen even if the user is on a space containing a full screen app?

I know this is possible when the app is LSUIElement=true (an app without a position in the Dock), but mine isn't.

how did you know this only works when LSUIElement=true ? Is it documented somewhere ? I spend a day with different configurations until I reach the same conclusion, it only works with LSUIElement=true. Is there a way of getting this same behaviour to work with LSUIElement=false ? — alfonsodev

radex radex · Accepted Answer · 2016-03-24T17:12:01

Okay, I had the right idea, the tricky part is how all the options interact with each other. Here's what works:

NSPanel, not NSWindow
style mask: [.borderless, .nonactivatingPanel]

And these properties:

panel.level = .mainMenu
panel.collectionBehavior = [.canJoinAllSpaces, .fullScreenAuxiliary]

Swift 4.2 Code

Create and show a panel using these settings. Then you can drag the panel onto a fullscreen app (dual monitor setup).

let panel2 = NSPanel(contentRect: NSRect(x: 0, y: 0, width: 200, height: 200), styleMask: [.titled, .nonactivatingPanel], backing: .buffered, defer: true)
panel2.level = .mainMenu
panel2.collectionBehavior = [.canJoinAllSpaces, .fullScreenAuxiliary]
panel2.orderFrontRegardless()

Switching to borderless will prevent the user from moving your window.

let panel2 = NSPanel(contentRect: NSRect(x: 0, y: 0, width: 200, height: 200), styleMask: [.borderless, .nonactivatingPanel], backing: .buffered, defer: true)
panel2.level = .mainMenu
panel2.collectionBehavior = [.canJoinAllSpaces, .fullScreenAuxiliary]
panel2.orderFrontRegardless()

Allow an NSWindow (NSPanel) to float above full screen apps

3 Answers