Странное поведение окон

void __fastcall TForm2::CreateParams(Controls::TCreateParams &Params)
{
    TForm::CreateParams(Params);
    Params.ExStyle |= WS_EX_APPWINDOW;
    Params.WndParent = NULL;
}//---------------------------------------------------------------------------

if(OpenDialog->Execute())
{
 
}

if(OpenDialog->Execute(this->Handle))
{
 
}

TForm3 *Form3 = NULL;

void __fastcall TForm2::AL_CloseExecute(TObject *Sender)
{
    if(Form3)
    {
        Form3->ModalResult = mrCancel;
    }
    Close();
}
//---------------------------------------------------------------------------
void __fastcall TForm2::Button1Click(TObject *Sender)
{
    Form3 = new TForm3(this);
 
    __try
    {
        Form3->ShowModal();
    }
    __finally
    {
        delete Form3;
        Form3 = NULL;
    }
}

//---------------------------------------------------------------------------
void __fastcall TForm2::FormCloseQuery(TObject *Sender, bool &CanClose)
{
    CanClose = !IsExistsChildForms(this);
}
//---------------------------------------------------------------------------
bool __fastcall IsExistsChildForms(TForm *Form)
{
    for(int i = 0; i < Form->ComponentCount; i++)
    {
        if(Form->Components[i]->InheritsFrom(__classid(TForm)))
        {
            return true;
        }
    }
 
    return false;
}
//---------------------------------------------------------------------------