[Setup]
AppName=MyApp
AppVerName=MyApp
DefaultDirname={pf}\MyApp

[Files]
Source: compiler:innocallback.dll; DestDir: {tmp}; Flags: dontcopy

[code]
type
   TCallbackProc = function(h:hWnd;Msg,wParam,lParam:Longint):Longint;
    
function SetWindowLong(Wnd: HWnd; Index: Integer; NewLong: Longint): Longint; external 'SetWindowLongA@user32.dll stdcall';
function WndProcCallBack(P:TCallbackProc;ParamCount:integer):LongWord; external 'wrapcallback@files:innocallback.dll stdcall';
function CallWindowProc(lpPrevWndFunc: Longint; hWnd: HWND; Msg: UINT; wParam, lParam: Longint): Longint; external 'CallWindowProcA@user32.dll stdcall';
function SetWindowPos(hWnd: HWND; hWndInsertAfter: HWND; X, Y, cx, cy: Integer; uFlags: UINT): BOOL; external 'SetWindowPos@user32.dll stdcall';

var
Form1: TForm;
OldProc: Longint;

function MyProc(h: HWND; Msg, wParam, lParam: longint): Longint;
begin
   if Msg=$3 then SetWindowPos(Form1.Handle, 0, WizardForm.Left+WizardForm.Width+5, WizardForm.Top, 0, 0, $515);
   Result:= CallWindowProc(OldProc, h, Msg, wParam, lParam);
end;

procedure InitializeWizard();
begin
   Form1:= TForm.Create(MainForm);
   Form1.SetBounds(WizardForm.Left+WizardForm.Width+5, WizardForm.Top, 100, 358);
   Form1.BorderStyle:= bsSingle;
   Form1.Show;
    
   OldProc:= SetWindowLong(WizardForm.Handle, -4, WndProcCallBack(@MyProc, 4));
end;

procedure DeinitializeSetup();
begin
   SetWindowlong(WizardForm.Handle, -4, OldProc);
end;