ShellExecuteEx .html not registered SE_ERR_NOASSOC (when running from Delphi-Debugger)

Question

In the moment, I got a problem trying to open an URL (like http://example.com/test/customer.html?sessionid=291697) with ShellExecuteEx. My goal is to see it in the registered standard browser (e.g. Firefox, IE, Chrome...)

procedure RunNoWait(AProgram: string; AParameters: string; AWorkingDirectory: string; AUAC: Boolean; AShow: Integer = SW_SHOWNORMAL);
var
  sei: TShellExecuteInfoW;
  aRes: Boolean;
begin
  // Does not work too:
  //  aRes := ShellExecute(Application.Handle, 'open', PWideChar(AProgram), 0, 0, SW_SHOW);
  //  if aRes <= 32 then begin
  //    RaiseLastOSError;
  //  end;

  FillChar(sei, SizeOf(sei), 0);
  sei.cbSize := SizeOf(sei);
  sei.Wnd := Application.Handle;
  sei.fMask := SEE_MASK_FLAG_DDEWAIT or SEE_MASK_FLAG_NO_UI or SEE_MASK_NOCLOSEPROCESS;
  if AUAC then begin
    sei.lpVerb := PWideChar('runas'); 
  end
  else begin
    sei.lpVerb := PWideChar('open');
  end;
  sei.lpFile := PWideChar(WideString(aProgram));
  sei.lpDirectory := PWideChar(WideString(AWorkingDirectory));
  sei.lpParameters := PWideChar(WideString(AParameters));
  sei.nShow := AShow;

  aRes := ShellExecuteExW(@sei);
  try
    if not aRes then begin
      RaiseLastOSError;
    end;

  finally
    CloseHandle(sei.hProcess);
  end;
end;

// later, I call this with:
  AAddress := 'http://example.com/test/customer.html?sessionid=291697';
  RunNoWait(AAddress, '', '', False);

The WinApi returns GetLastError 1155 (ERROR_NO_ASSOCIATION) and FormatError returns 'There is no application associated with the specified file name extension.'.

When I copy the URL into Windows Explorer, the website is opened in Firefox, for example...

Any ideas, why the URL cannot be opened programmatically?

[edit:] Just found out, that it works with standard browser set to Microsoft Edge... But still doesn't work with Firefox, IE and Chrome. And I can easily open the URL with those browsers manually...

[edit:] One more hint: while testing with standard-browser IE, I noticed, that it works, when IE is already open(???)

[edit:] The Problem only exists when starting the app from Delphi-Debugger. Does anybody know why?

Answer 1

After all, I see, that I was looking into the wrong direction:

The problem existed only, when starting the app from Delphi Debugger.

All browsers work, if you start the app without Delphi.

[edit:] Just found out why: Tools->Options->Debugger-Options->Embarcadero-Debugger->'debug in spawned processes' was active. Seems like those browsers do not want to get debugged... (anyway, we have no source for them)