Here's how it went:
Pale Moon 27 (Tycho platform) did support Vista (and higher), but not XP; the New Moon 27 fork was created by @roytam1 to restore WinXP support; I can assure you that NM27 runs on Vista just as good (possibly better) as it does on WinXP...
Then Moonchild Productions created Pale Moon 28, built on the UXP platform; UXP forked MozillaESR 52, which did support both XP+Vista; but Moonchild Productions removed both these OSes from their forked platform, so that UXP now supports Win7+.
To the rescue came, again, @roytam1 , who restored support in UXP for BOTH WinXP and Vista; in fact, New Moon 28 and Serpent 52.9.0 are almost the only browser choices for Vista users nowadays, browsers which are under continued development and not EOL'd...
And when have I disputed that? I merely said:
Unless numerous other members (on XP/Vista/whatever) come forth here with the same affliction as yours, i.e. severe performance degradation of New Moon 28 as the result of the ported (from Australis) audio-tab-icon enhancement, let's, for the sake of argument, assume that, for the time being, what you're experiencing has to somehow do with your own setup(s).
For the record, the last NM28 build without the feature was (x86):
palemoon-28.2.0a1.win32-git-20181117-c94825c86-xpmod.7z
and this feature/enhancement was introduced first in (x86):
palemoon-28.2.0a1.win32-git-20181124-b37e8f87c-xpmod.7z
(and is still present in latest build...); so people reading this should test and report back, if this is to be troubleshot...
Calm down, please ! You have to understand first that the New Moon 28 builds are provided by @roytam1 as a pure courtesy to WinXP and Vista users and under no circumstances is he any part of the decision making with regards to browser features that get implemented (or not!); the entire browser code is being modified upstream by the Moonchild dev team, @roytam1 only intervenes to the extent of making that code successfully compile and run on XP+, NOTHING MORE... This has been explained before in this thread, but I suspect its sheer size has now become a deterrent for new members to read it...
If you have a gripe about this feature, you should've directed your frustration over at Moonchild et company, not at Roy; but Moonchild only support "new" Win OSes (Win7+) and "new" hardware, so even that is a moot point...
To re-iterate, you may indeed have a genuine issue on your setup, but:
1. It's wrong to generalise as if every NM28 user on every possible configuration has that same issue (and issue directives/guidelines as to what people should or shouldn't install in their browsers)...
2. Even if you're the only one with the problem, you'd have to provide ample details and reproduction steps to the current maintainer so he's in a position to first reproduce and, second, hopefully offer you some fixes for it...
FYI, the code in the upstream repo that implemented this enhancement you detest is covered in UXP Pull Request #874:
https://github.com/MoonchildProductions/UXP/pull/874
You'll find there all links to individual commits...
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OT: Maybe it's my own false sense, but to me you're coming off as a tad aggressive in your last two posts (of a total of 3); this isn't very becoming of "new" members, especially when you expect feedback/help from other members here - we are all volunteers and, of course, no one is perfect, but we do try our best to help (at least I do... ).