Required Window List Keys The keys that are guaranteed to be available in a window’s information dictionary. TopicsConstantskCGWindowNumberkCGWindowStoreTypekCGWindowLayerkCGWindowBoundskCGWindowSharingStatekCGWindowAlphakCGWindowOwnerPIDkCGWindowMemoryUsage See AlsoConstantsWindow Sharing ConstantsBacking Store TypesWindow List Option ConstantsWindow Image TypesCGWindowID Encoding TypeNull WindowWindow Sharing Encoding TypeWindow Backing Encoding TypeOptional Window List Keys