property OnReleased: TNotifyEvent;
The OnReleased event occurs when the user clicks the the pressed CaptionButton on title bar or selects in the SystemMenu the checked menu item associated with this button.
When user clicks (unpress) the button which could be pressed (this controlled by AllowPress property), the button state will changed to up, Down property will be False and associated menu item in the system menu will be unchecked (if SystemMenu.ApplyToMenu is True).
AllowPress, Down, SystemMenu properties.
OnClick and OnPressed events.