numberOfSuppressedNotificationPanels

The number of NotificationPanels that were suppressed and thus not present in activeNotificationPanels. Note that not all NotificationPanels absent from activeNotificationPanels are counted as suppressed. Suppressed NotificationPanels may become simply hidden instead after being presented to the user manually, at which point they're not present in activeNotificationPanels and not counted in numberOfSuppressedNotificationPanels.