I'm trying to make a window (NSWindow) visible on all the spaces including other full screen app windows. I've been trying to set a higher window level as well as playing with expose and spaces settings in the inspector. I found some solutions here, but they do not work. At least on El Capitan.
Here is a sample code to test:
let window = NSWindow(contentRect: NSRect(x: 300, y: 300, width: 200, height: 200), styleMask: NSBorderlessWindowMask, backing: .Buffered, `defer`: true)
window.backgroundColor = NSColor.greenColor()
window.level = Int(CGWindowLevelForKey(.FloatingWindowLevelKey))
window.collectionBehavior = [.CanJoinAllSpaces, .Transient]
window.makeKeyAndOrderFront(nil)
Now it displays the window on all the desktop spaces but it does not display it over the full screen windows of other apps.