AS A PRECAUTION MAKE A COPY FOR BACKUP OF YOU CustomizeToolbar.dat & CustomizeToolbar.btn (Path: %AppData%\Roaming\Notepad++\plugins\config\ ) in case of conflict with any prior version.

Install:

1. Build with C++ VS 2022, "Release x64" config

2. Copy "CustomizeToolbar.dll" to %ProgramFiles%\Notepad++\plugins_CustomizeToolbar\ folder

3. Launch Notepad++, goto Plugins~"Customize Toolbar" menu and click "Custom Buttons", and close Notepad++ (NPP)

4. Goto %AppData%\Roaming\Notepad++\plugins\config\

5. The files, "CustomizeToolbar.btn" (Custom Button config text file) & "CustomizeToolbar.dat" (your personal Customized Toolbar settings are saved here), are auto generated

6. For Custom Buttons, modify the CustomizeToolbar.btn file entering NPP menu paths (comma-deliminated, up to 4-levels deep), and add icon filepath(s) that exist on your system (up to 3 icons).

   a. CustomizeToolbar.btn line example with 3 icons:

         Plugins,Compare,Navigation Bar,,standard-3.bmp,fluentlight-3.ico,fluentdark-3.ico
   

   To comment-out line, use ";"

Notes:

1. This is just @dave-user 's plugin, I only add and tweaked a couple lines and added files for Visual Studio 2022 to compile.

    a. I have only a miniscule knowledge of C++ or Notepad++ plugins so I am unable to maintain this
      further. I truely hope someone is able to continue to update
      CustomizeToolbar
   
    b. Suggestions Welcome, but include instructions.
   

2. All Icons should be saved as 24-bit Bitmap (.bmp) and renamed to .ico. This is generally the universal case for icons used in Notepad++ (Notepad-Plus-Plus). This can be done with MSPaint.exe by default.