title: Inno Setup custom form is hiding beneath installation page
body: <p>We are showing custom form during [Run] section in interactive installation. But custom form is hiding beneath installation page. Is any way to show the custom form on installer like message boxes.</p>
  
  <p>Using below code to create custom form. and calling it in [Run] section.</p>
  
  <pre><code>[Setup]
  AppId=Display Form
  AppName=Display Form
  DefaultDirname={sd}\Test
  DisableDirPage=yes
  WindowVisible=no
  OutputDir=C:\Test
  [Run]
  Filename: C:\Test.exe; Flags: runhidden; AfterInstall : PassphraseForm;
  [Code]
  Procedure PassphraseForm();
  var
    Form: TSetupForm;
    OKButton: TNewButton;
    mLabel:TLabel;
    LogFileString : AnsiString;
    RichEditViewer: TRichEditViewer;
    cancelclick: Boolean;
  begin
  
  Form := CreateCustomForm();
  try
  Form.ClientWidth := ScaleX(400);
  Form.ClientHeight := ScaleY(180);
  Form.Caption := 'Server';
  Form.Center
  mLabel:=TLabel.Create(Form);
  mLabel.Caption:='';
  mLabel.AutoSize:=True;
  mLabel.Alignment:=taCenter;
  
  OKButton := TNewButton.Create(Form);
  OKButton.Parent := Form;
  OKButton.Width := ScaleX(70);
  OKButton.Height := ScaleY(30);
  OKButton.Left := ScaleX(170);
  OKButton.Top := ScaleY(142);
  OKButton.Caption := 'OK';
  OKButton.ModalResult := mrOk;
  
  RichEditViewer :=TRichEditViewer.Create(Form);
  RichEditViewer.Width :=360;
  RichEditViewer.Height :=120;
  RichEditViewer.Top := 20;
  RichEditViewer.Left :=20;
  RichEditViewer.Alignment:=taLeftJustify;
  RichEditViewer.Parent := Form;
  RichEditViewer.WordWrap :=True;
  RichEditViewer.ScrollBars := ssBoth;
  RichEditViewer.UseRichEdit := True;
  RichEditViewer.Font.Size:=9;
  RichEditViewer.RTFText := 'Server Value'; 
  
  RichEditViewer.ReadOnly := True;
  Form.ActiveControl := OKButton;
  cancelclick:=True;
  if Form.ShowModal() = mrOk then
  begin
    Log('Custom form is displayed succesfully');
  end;
  finally
  Form.Free();
  end;
  end;
  </code></pre>