Unable to force multiplied versions to use individual icons - due to lack of unique AppUserModelID support?

[GitHubinatrix]

I use multiple Notepa3 portable instances simultaneously - each being associated-to by just one unique file that has a fake TXT_something extension. Each EXE has a unique name and got its icon changed [with Resource Hacker 5.2.8]. This combination allows me to distinguish both the EXEs and text files at a glance. My most important "fake" TXT file is pinned to the Taskbar thus available through context menu of its EXE icon that sits on Taskbar

But it seems that on my Windows 10 I can either:

A] Have each of opened texted files that bear a different fake extension use their unique icon - but that important one will not use the spot already taken by its pinned EXE when it becomes opened, but instead will show up under a second iteration of its icon. This double room taken by the main file wastes the precious room on Taskbar

B] Adjust the Target of the pinned EXE to include path to its unique TXT - but then all other fake TXTs formats will open up using the icon of that pinned one, despite still being run via their individual EXEs; plus the first opened such TXT will always reuse the spot of the pinned one. This renders the whole multiplication of EXEs useless as there is no visual distinction anymore; plus any of them can extra confuse me as being the main pinned one

I do have in every EXE its option of

Settings > Window > Reuse Window

turned off. And I also tried using a MANIFEST file e.g.

<?xml version="1.0" encoding="UTF-8"?>
<assembly xmlns="urn:schemas-microsoft-com:asm.v1" manifestVersion="1.0">
  <application>
    <windowsSettings>
      <AppUserModelID>Notepad3.TXT_01</AppUserModelID>
    </windowsSettings>
  </application>
</assembly>

But the trade-off situation still prevails. And this was not happening when I was using Notepad 2- i.e. I had my main file pinned to Taskbar with its Target changed, thus it was always taking one spot, while all other versions were using their individual icons and never posing as the main one by taking its spot

Is it because Notepad3 does not programmatically set or honor AppUserModelIDs per instance or file?

[GitHubinatrix]

[I just reworked my original post in order to better explain what is happening and when]

[jupester]

You can set unique values in the ini file, so you'd need to use unique ini's per exe

[Settings2]
ShellAppUserModelID=

[GitHubinatrix]

But I have been using individual INI files all that time

Now I went to Notepad3 TXT_01.ini and added at its top

[Settings2]
ShellAppUserModelID=test_id_1

and then in Notepad3 TXT_02.ini added

[Settings2]
ShellAppUserModelID=test_id_2

but the behavior is the same - i.e. the Notepad3 TXT_01.exe pinned to Taskbar open its [modified by me] Target of

"C:\Notepad3 multiple versions\Notepad3 V01.exe" "C:\text files\test.txt_01"

under a new icon instead of using the already occupied space

[jupester]

added at its top

What do you mean by that, there should already be a [Settings2] section, did you definitely add that key to that already existing section?, make sure you don't add it in [Settings] section either.

Also I would assume you will need to re-pin any already pinned items to the taskbar, and pin them as plain items first, not ones that already link to specific files.

Anyway I am just passing along the info of how to set a custom ShellAppUserModelID, in the past I remember setting up something similar to what you are want using this method, and I got it working, but it wasn't recently.

[GitHubinatrix]

When I initially opened Notepad3 TXT_01.ini it did not have [Settings2] section- it must have got somehow deleted during my tests of it, back then when I was still using multiple copies of Notepad2 on the same system [which worked without a sweat i.e. without a need to mingle with their INI files]. And so, when I opened as second one the Notepad3 TXT_02.ini I did not looked in it for [Settings2] and thus inadvertently doubled it

But I have been pinning and unpinning the Notepad3 TXT_01.exe all that time. But even now after repeating the test only after a reset of the system and using a different pair of EXEs and with [Settings2] in their original place I still get a second icon on Taskbar for this TXT which has its EXE pinned to it with, no matter if the EXE still has a right-click submenu or not because I unpin the TXT itself and change the Target to e.g.

"C:\Notepad3 multiple versions\Notepad3 V04.exe" "C:\text files\test.txt_04"

And yes, the TXT_04 is associated to that particular EXE, because I used such REG file:

Windows Registry Editor Version 5.00

[HKEY_CURRENT_USER\SOFTWARE\Classes\.txt_04]
@="TXT_04_file___associated_via_REG_script"

[HKEY_CURRENT_USER\SOFTWARE\Classes\TXT_04_file___associated_via_REG_script\shell\open\command]
@="\"C:\\Notepad3 multiple versions\\Notepad3 V04.exe\" \"%1\""

[GitHubinatrix]

I have switched from running on Windows 10 Enterprise 20H2 x64 [10.0.19042] to Windows 10 IOT Enterprise LTSC 21H2 x64 [19044.6575] and the issue prevails - and along my question about its possible culprit:

Is it because Notepad3 does not programmatically set or honor AppUserModelIDs per instance or file?