How to detect which application execute my program in Delphi?

Question

I want to find the executer app of my Delphi app.

For example, if a file named "a.exe" executes another file "b.exe" then "b.exe" should show "a.exe" in a message.

I wrote a Delphi program like this:

uses
  ...PsApi, TlHelp32;

type
  TForm1 = class(TForm)
    procedure FormCreate(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
    function FindParentProcess(): String;
  end;

var
  Form1: TForm1;

  //Boolean
  ParentProcessFound: Boolean;

  //DWORD
  CurrentProcessID, ParentProcessID: DWORD;

  //String
  ParentProcessPath, WhichParentProcess: String;

  //THandle
  HandleParentProcess, HandleSnapShot: THandle;

  //TProcessEntry32
  EntryParentProcess: TProcessEntry32;

implementation

{$R *.dfm}

function TForm1.FindParentProcess;
const
  BufferSize = 4096;
begin
  ParentProcessFound := False;

  HandleSnapShot := CreateToolhelp32Snapshot(TH32CS_SNAPPROCESS, 0);

  if HandleSnapShot <> INVALID_HANDLE_VALUE then begin
    EntryParentProcess.dwSize := SizeOf(EntryParentProcess);

    if Process32First(HandleSnapShot, EntryParentProcess) then begin
      CurrentProcessID := GetCurrentProcessId();

      repeat
        if EntryParentProcess.th32ProcessID = CurrentProcessID then begin
          ParentProcessID := EntryParentProcess.th32ProcessID;
          HandleParentProcess := OpenProcess(PROCESS_QUERY_INFORMATION or PROCESS_VM_READ, False, ParentProcessID);

          if HandleParentProcess <> 0 then begin
            ParentProcessFound := True;
            SetLength(ParentProcessPath, BufferSize);
            GetModuleFileNameEx(HandleParentProcess, 0, PChar(ParentProcessPath), BufferSize);
            CloseHandle(HandleParentProcess);
          end;
          break;
        end;
      until not Process32Next(HandleSnapShot, EntryParentProcess);
    end;
    CloseHandle(HandleParentProcess);
  end;

  if ParentProcessFound then begin
    Result := ParentProcessPath;
  end else begin
    Result := '';
  end;
end;

procedure TForm1.FormCreate(Sender: TObject);
begin
  WhichParentProcess := FindParentProcess;

  ShowMessage(WhichParentProcess);
end;

end.

And I wrote a program (test.exe) which will execute my Delphi app:

#include <iostream>
#include <windows.h>
using namespace std;

int main()
{
    ShellExecute(NULL, "open", "Project1.exe", NULL, NULL, SW_NORMAL);

    return 0;
}

But the problem is Project1.exe shows itself (Project1.exe) instead of "test.exe".

How to detect which application run my Delphi program?