请问为什么动态生成的WebBrowser不能正常显示？(20分)

procedure TForm1.Button1Click(Sender: TObject);
var
panel:tpanel;
wb:twebbrowser;
begin
panel:=tpanel.Create(self);
panel.Align:=alclient;
panel.Parent:=self.TeThemeTabControl1;

wb:=twebbrowser.Create(self);
wb.ParentWindow:=panel.Handle;
wb.Align:=alclient;
end;
////////
为什么wb不是alclient的呢？

uses ShDocVw;

http://www.delphibbs.com/delphibbs/dispq.asp?lid=986903

改为：
procedure TForm1.Button1Click(Sender: TObject);
var
panel:tpanel;
wb:twebbrowser;
begin
panel:=tpanel.Create(self);
panel.Align:=alclient;
panel.Parent:=self.TeThemeTabControl1;
wb:=twebbrowser.Create(self);
panel.insertcontrol(wb);//webbrowser是Activex不能指定parent

wb.Align:=alclient;
end;