It is possible to create an application that once run, will not appear on the task bar or appear in the currently running applications window. This is accomplished by setting the Application.ShowMainForm := False;. The source below illustrates an example DPR file.

program Project1;

uses
  Forms,
  Unit1 in 'Unit1.pas' {Form1};

{$R *.res}

begin
  Application.Initialize;
  Application.ShowMainForm:=False;
  Application.CreateForm(TForm1, Form1);
  Application.CreateForm(TForm2, Form2);
  Application.Run;
end.

In Windows 2000 the application will appear in the Processes tab. This is also where you would terminate the program as well.

Setting ShowMainForm to false allows for an application to run similar to that of a service. Great for applications that need to constantly check for external events or conditions to occur.

other

procedure TForm1.Button1Click(Sender: TObject);

var
  frmRegion, tempRegion: HRGN;
  i: Integer;
  Arect: TRect;
Begin
  frmRegion := 0;
  for I:= 0 to ControlCount - 1 Do
     begin
       aRect := Controls[i].BoundsRect;
       OffsetRect( aRect, clientorigin.x - left, clientorigin.y - top );
       tempRegion := CreateRectRgnIndirect( aRect );
       if frmRegion = 0 Then
          frm Region := tempRegion
       else
          begin
             CombineRgn( frmRegion, frmRegion, tempRegion, RGN_OR );
             DeleteObject( tempRegion );
          end;
     end;
  CombineRgn( frmRegion, frmRegion, tempRegion, RGN_OR );
  SetWindowRgn( handle, frmRegion, True );
  DeleteObject( tempRegion );
end;