在所有窗口后面的Background窗体：
procedure CreateParams ( var Params : TCreateParams ); override ;
public
{ Public declarations }
end ;
var
Form1 : TForm1 ;
implementation
{$R *.dfm}
procedure TForm1 . CreateParams ( var Params : TCreateParams );
begin
inherited CreateParams ( Params );
if Assigned ( Application . MainForm ) then
begin
Params . WndParent := GetDesktopWindow ;
Params . Style := WS_CHILD ;
end ;
end ;