procedure TForm1.Button1Click(Sender: TObject);
var
h: HWND;
FormStyle: Integer;
begin
h := self.Handle;
FormStyle := GetWindowLong(h, GWL_EXSTYLE);
SetWindowLong(h, GWL_EXSTYLE, FormStyle or WS_EX_LAYERED);
SetLayeredWindowAttributes(h, 0, 128, LWA_ALPHA);
end;

procedure TForm1.Button2Click(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
       frmRegion := tempRegion
     Else Begin
       CombineRgn( frmRegion, frmRegion, tempRegion, RGN_OR );
       DeleteObject( tempRegion );
     End;
   End;
   tempregion :=
     CreateRectRgn( 0, 0, Width,
                    GetSystemMetrics( SM_CYCAPTION )+
                    GetSystemMetrics( SM_CYSIZEFRAME )+
                    GetSystemMetrics( SM_CYMENU ) * Ord(Menu <> Nil));

   CombineRgn( frmRegion, frmRegion, tempRegion, RGN_OR );
   DeleteObject( tempRegion );
   SetWindowRgn( handle, frmRegion, true );
end;