kCGAssistiveTechHighWindowLevelKey
kCGBackstopMenuLevelKey
kCGBaseWindowLevelKey
kCGCursorWindowLevelKey
kCGDesktopIconWindowLevelKey
kCGDesktopWindowLevelKey
kCGDockWindowLevelKey
kCGDraggingWindowLevelKey
kCGFloatingWindowLevelKey
kCGHelpWindowLevelKey
kCGMainMenuWindowLevelKey
kCGMaximumWindowLevelKey
kCGMinimumWindowLevelKey
kCGModalPanelWindowLevelKey
kCGNormalWindowLevelKey
kCGNumberOfWindowLevelKeys
kCGNumReservedWindowLevels
kCGOverlayWindowLevelKey
kCGPopUpMenuWindowLevelKey
kCGScreenSaverWindowLevelKey
kCGStatusWindowLevelKey
kCGTornOffMenuWindowLevelKey
kCGUtilityWindowLevelKey