Description of HKMessageReceiver :
HKMessageReceiver is a non visual component, that added to a form, makes it able to receive messages sent or posted at application.handle. It has an event that is called when all WM_USER messages are broadcast. This way you can give large programs polymorphism, and make and forget about forms that do something when something has changed in your program. If the form is not open, no harm done, the message is ignored. Source included. Tested with Delphi 4.