Private tab script again stopped working in Firefox version 134

[kaos-55]

Recently I just updated Firefox to version 134 however after restarting Firefox to apply the update the new private tab button disappeared and the shortcut key does not work.
I don't know what changes Firefox made to make the script break again, if anyone knows how to fix it or a way to debug the script to make it work again I would appreciate it.

[dimdamin]

Private tab script work for me, but the problem is a bug 1930654 need an update for userChrome.mjs. You can try changing line 169

-    aSubject.addEventListener('DOMContentLoaded', this, {once: true});
+    aSubject.addEventListener('DOMContentLoaded', this, {once: true, mozSystemGroup: true});

PS. Not All script work correctly!!!

[kaos-55]

@dimdamin Thanks for the fix. After updating the userchrome.mjs and restarting Firefox, I saw that the script still didn't appear and was going to say it didn't work, but then I remembered that I had to clear the startup cache and the script worked again🤦‍♂️

[kaos-55]

Now I found a small bug in the script, when the browser is restarted, the new private tab button stays next to the list all tabs button and not next to the new tab button where it always stays. Moving any button on the tab bar in the Customize Toolbar option restores its behavior, but the bug returns when the browser is restarted 🤷🏻‍♂️

When the browser starts (Wrong position)

When moving any button on the tab bar (Normal position)