Description of the Issue

Dark mode not working In Windows 10 21H2

Steps to Reproduce the Issue

Debug Information

Notepad++ v8.1.9.1 (32-bit)
Build time : Nov 13 2021 - 15:20:19
Path : C:\Program Files (x86)\Notepad++\notepad++.exe
Command Line :
Admin mode : OFF
Local Conf mode : OFF
Cloud Config : OFF
OS Name : Windows 10 Enterprise (64-bit)
OS Version : 2009
OS Build : 19044.1348
Current ANSI codepage : 1252
Plugins : mimeTools.dll NppConverter.dll NppExport.dll