type
TForm1 = class(TForm)
private
...
protected
procedure CreateParams(var Params: TCreateParams); override;
public
...
end;
.....
procedure TForm1.CreateParams(var Params: TCreateParams);
begin
inherited CreateParams(Params);
with Params do begin
WndParent := GetDesktopwindow;
ExStyle := ExStyle or WS_EX_TOPMOST;
end;
end;