Specifies which object will start running when F5 is pressed.
Level: Environment
By default, the Startup Object property is set to "(none)". In this case, when pressing F5 the Launchpad Tool Window is opened.
When you set a specific object for this property, it will be the one that starts when pressing F5.
This property applies only at design time.
Setting an Object as Startup Object
Unsetting a Startup Object