Wednesday, August 28, 2019

Preference Panes and Catalina

Paul Kim:

System Preferences has had a major change: preference panes now load in a separate process. Apple ones get their own while all the third party ones get stuck in a process called “legacyLoader (System Preferences)”.


The other problem is that magenta. What is that? Apparently, it’s a security feature. Any windows besides the main preference window will have their transparent areas colored magenta. I’ve been trying to pin down the rules as to when this occurs but it’s been slow going and also the screenshot above contradicts what I’ve been told. Note that my software is notarized so it’s not like this is only applying to unknown software.


To top this all off: none of this has been announced or documented. I’ve only found out about this through backchannels and then later, via a “conversation” via Feedback Assistant (FB6758586).

The lack of documentation makes it take longer to find out about and adapt to these types of changes. It also adds a layer of uncertainty: it’s not clear how things are intended to work, so weird behavior that you see could be by design or something that’s in the process of being fixed or an unknown bug.


Update (2019-08-30): Paul Kim:

Paraphrased response from Apple regarding my pref pane dark mode bug which you can replicate with a newly created project in Xcode with no added code: “Here are some things to check in your code, oh, and could you provide a sample project?”

What deeply worries me is that they apparently aren’t QA-ing with third party panes since an empty pane is the most basic thing you can have.

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I could have sworn the separate process model for preference panes was introduced in something like 10.6 or 10.7. The smoothness of selecting and switching panes dropped dramatically in one of those major releases due to that.

This is what I was remembering above: (

HN comments from users who would definitely know pointed to pane process isolation, so this dated back to at least 10.10. Responsiveness never recovered.

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