TWinControl.OnExit
From OpenEUO
EV OnExit Occurs when the input focus shifts away from one control to another.
Use the OnExit event handler to provide special processing when the control ceases to be active. The OnExit event does not occur when switching between forms or between another application and your application. When switching between controls in separate container controls such as the TPanel and the TGroupBox controls, an OnExit event occurs for the control inside the container before the OnExit event of the container.
