关于MDI窗口！

[adams_here]

父窗口下，新建一个子窗口后再关闭这个子窗口然后再新建一个子窗口，报错：
Project *.exe raised exception class EAccessViolation with message 'Access violation at address ** in module **.Read of address **'.
其中子窗口中已定义了
procedure Tfaddhy.FormClose(Sender: TObject; var Action: TCloseAction);
begin
action:= caFree;
end;

[andylife]

我想看看建立字窗口的代码？

[adams_here]

建立子窗口的代码如下:
if not assigned(faddhy) then
application.CreateForm(tfaddhy,faddhy);
faddhy.Show;

[shehyde]

if not Assigned(FindComponent('ChildForm')) then
ChildForm := TChildForm.Create(Self)
else if ChildForm.WindowState = wsMinimized then
ChildForm.WindowState := wsNormal
else
ChildForm.Show;