Is that a statement about future Firefox visions or Firefox 57? I assume you know the gritty details while I'm a rather confused Firefox power user / fan / advocate (using .. addons that are affected, vertical tabs/tree style tabs plus vimperator/pentadactyl mostly).
The outrage The Internet™ seems to feel is probably not about XUL being deprecated/killed. I'd say no user cares about the technology, the only people even caring are probably the addon developers.
From what I can tell, the outrage is mostly due to the impression (and I dearly hope that you will dismiss this as wrong, just like the 'addon limitation' reference above) that the web extension switch happens before popular, polarizing addons are even remotely possible given the new API.
"Will not have this limitation", as in "it won't support that use case in 57 at all" or as in "you can do better than this Chrome extension you describe"?
You're basically correct about the APIs, though. Developers of some popular add-ons don't know when or if the APIs they need will be implemented. Support for migrating gradually (embedded WebExtensions) was just released in 51 and will be gone in 57 -- not even a full ESR cycle.
Developer burnout is a problem, too. This comes right after many of them put in significant work making their now-deprecated code multiprocess-compatible, which came after mandatory extension signing, which came after a bunch of UI changes. It's not surprising some of them have quit.
Most of these changes and their timelines are motivated by fundamental architectural work happening deep down in Firefox. We're doing the best we can to get as many add-on APIs in place before 57, but for heavy add-on users, it has the potential to be a rough transition.
For deeper meddling in the browser, and for APIs that don't yet exist, WebExtension Experiments (https://webextensions-experiments.readthedocs.io/en/latest/i...) should provide a reasonable option. Basically, you can keep using old-style "bootstrapped" add-ons in DevEdition and Nightly. Kind of an explicit way to opt-out of API stability guarantess so we can continue refactoring the browser core. Experiments are intended for prototyping new WebExtension APIs for eventual inclusion into mainline Firefox, but you could also use them for power-user APIs, so long as you don't mind the maintenance burden.
Can you clarify/elaborate? Last I heard, UI modification by web extensions was still unconfirmed at best.
Can I use this to replace the entire browser history system and omnibar autocomplete with a custom one?
Can I use this to replace the entire browser chrome?
Some of these changes I need (AutoHiDPI) to use a browser at all. Others I wish for. All of them I currently am using.
The alternative is me staying on an ancient browser, or forking Firefox and browsing with a horribly outdated and barely patched version. Or reading HN with a magnifying glass.
Generally, the way forward will be to use WebExtension Experiments (https://webextensions-experiments.readthedocs.io/en/latest/i...), which let you run classic-style "bootstrapped" add-ons in Firefox Developer Edition or Nightly. The intended use is for prototyping new WebExtension APIs for eventual inclusion into mainline Firefox, but nothing limits you to that usage.
In fact, the per-screen HiDPI setting even has an environment variable on most Linux systems (Qt’s QT_SCALE_FACTORS), but Firefox completely ignores that.
I don’t have the time anymore to rewrite half the UI stack of every single application I use, and then take over maintenance of that. I’ve done that with a few open source projects, but my time is limited. And if I wanted to implement extending the UI properly, I’d definitely have to rewrite the entire stack, similar to what Browser.html does.
But neither of them is good enough. (Especially Palemoon’s UI is painful to look at, and hard to fix).
I can assure you that you only want this if you can guarantee that your add-ons only do what they claim, don't have security vulnerabilities, and are never acquired and maliciously updated. Otherwise, a permissionless add-on model means a bug in TreeStyleTabs could potentially be used to exfiltrate your entire password database, plant malicious binaries on your system, and destroy local data. If TST had limited permissions along the lines of only being able to manipulate tabs and their UI, that wouldn't be a problem.
> Have you seen "treestyletabs" implementation on chrome? It's a whole other window that has to be started an placed on the left of the screen by user because of the addon limitations.
Firefox will not have this limitation.