Patrik:

You have two ways:

1-You may set enable the closable property in the _screen, then you must put a exit menu with the quit command.
2-You must design your main form of the application in a MDI form and put the quit command in the unload method. This enable quit the app with the x.

Sorry for my English.

Pedro Pablo Giraudi
Cooperativa de Agua Potable de San Martín de los Andes
Provincia de Neuquén
Argentina