请大家给点意见（忠实的朋友）(100分)

我想开发个应用软件，其有工作区的概念，就是每个工作是独立的。请大家给个思路。
用delphi实现。MDI窗口，用Tab选择工作区。

只允许建立一次子窗体的MDI程序
procedure OpenChildForm(FormClass: TFormClass; var Fm; AOwner:TComponent);
var
I: Integer;
Child: TForm;
begin
for I := 0 to Screen.FormCount - 1 do
if Screen.Forms.ClassType = FormClass then
begin
Child := Screen.Forms;
if Child.WindowState = wsMinimized then
ShowWindow(Child.Handle, SW_SHOWNORMAL)
else
ShowWindow(Child.handle,SW_SHOWNA);
if (not Child.Visible) then Child.Visible := True;
Child.BringToFront;
Child.Setfocus;
TForm(Fm) := Child;
Exit;
end;
Child := TForm(FormClass.NewInstance);
TForm(Fm) := Child;
Child.Create(AOwner);
end;