Inno Setup custom form is hiding beneath installation page - inno-setup

Question

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.
Using below code to create custom form. and calling it in [Run] section.
[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;

Answer 1

OK, this is really nice (undocumented) feature of Inno Setup!
I had no idea [Run] section support AfterInstall parameter (it is not mentioned in manual :)
Anyway your code works fine for me:
I think there is no way displaying the form below the main form as it is created as Modal form and shown with Form.ShowModal().
Are you sure the form is not displayed somewhere else? E.g. on second monitor/screen or outside of screen borders?
Also check the debugger - maybe a breakpoint was hit just when form is about to show and you need to press F9 to continue.