How to use WinAppDriver to locate elements on Modal window of Modal window

I'm trying to automate a Windows Printer Driver Application on windows 10 pro with newest WinAppDriver v1.2.1.WinAppDriver. The test script cannot locate any element on the Preferences Window, which is a Modal window's Modal Window. The test scenario is as below:

1. The test script start notepad.exe, locate and click Print menu item, the Print Modal window shows.
2. Then locate and click the Preferences button on the Print Modal window, the Preferences Modal window shows.
3. Then try to click elements on the Preferences Modal Window, it fails.

Here is my sample code, using Appium-Python-Client library:

from appium import webdriver

desired_caps = {}
desired_caps["app"] = "C:\\Windows\\notepad.exe"
desired_caps["platformName"] = "windows"

driver = webdriver.Remote(
    command_executor='http://127.0.0.1:4723',
    desired_capabilities= desired_caps)

driver.find_element_by_name("ファイル(F)").click()
driver.find_element_by_accessibility_id("6").click()

# click elements on the Print modal window
driver.find_element_by_accessibility_id("1010").click()

# click elements on the Preferences modal window
driver.find_element_by_xpath("/Pane[@ClassName=\"#32769\"][@Name=\"デスクトップ 1\"]/Window[@ClassName=\"#32770\"][@Name=\"印刷設定\"]/Tab[@ClassName=\"SysTabControl32\"]/TabItem[@Name=\" 拡張機能 \"]").click() 
driver.find_element_by_xpath("/Pane[@ClassName=\"#32769\"][@Name=\"デスクトップ 1\"]/Window[@ClassName=\"#32770\"][@Name=\"印刷設定\"]/Button[@ClassName=\"Button\"][@Name=\"設定(E)...\"]").click()
driver.find_element_by_xpath("/Pane[@ClassName=\"#32769\"][@Name=\"デスクトップ 1\"]/Window[@ClassName=\"#32770\"][@Name=\"印刷設定\"]/Window[@ClassName=\"#32770\"][@Name=\"セキュリティ印刷設定\"]/CheckBox[@ClassName=\"Button\"][@Name=\"セキュリティ印刷(S)\"]").click()

The WinAppDriver's log:

{"status":7,"value":{"error":"no such element","message":"An element could not be located on the page using the given search parameters."}}

• I also have tried relative xpath expressions, and by name or by accessibility id. Did not succeed.
• I also have tried the WADLibrary client library. It had same phenomenon.
• I also have tried some other versions of WinAppDriver, all failed except the old version of WinAppDriver v1.1.4

Is there any other way to locate elements on the descendant Modal window, Preferences Modal window?

The second modal window (Preferences Modal window ) is actually treated as a new window(whose window handle is managed by winappdriver). After switching the session to that window, and using relative xpath, I solved the problem.