Performance issues related to the scalable UI (user interface).
Here's a list of important FAQs on scalable UI:
Question: Unlike Windows, why does the UI scale up much more when sliding from one stop to the next on macOS, though I am using the same monitor resolution?
Answer : The UI scales by factor 0.5 on macOS with each stop, but it increases by 0.25 on Windows. We plan to scale the UI for each stop by factor 0.25 on both Windows and macOS in the future releases.
Question: Why do we have lesser number of stops on macOS than on Windows for the same resolution on a monitor?
Answer: The parity between Windows and macOS is planned for future releases.
Question: Some users may compare Illustrator’s macOS behavior with InDesign's – why are the jumps in Illustrator for UI scaling more granular?
Answer: The UI scales by a factor 0.5 on macOS with each stop, but it increases by 0.25 in Ai on macOS. In the InDesign/InCopy future releases, each stop will scale the UI by the factor 0.25.
Question: What’s the reason for the slider being disabled?