With latest Safari preview release, Apple tweaks Pro Motion scrolling issue
Apple this week released a Safari Technology Preview update that among changes appears to address a problem that surfaced with its new MacBook Pro laptops and ProMotion adaptive refresh display software.
The problem came to light when owners of the laptops - which were just unveiled last month - began using Firefox, Chrome, and even Apple's own Safari browser on the MacBook Pro. They found scrolling was anything but smooth, despite the higher refresh rates offered by the new hardware.
Apple's release notes for Safari Technology Preview 135 say it has addressed "lazy image loading, and updated smooth scroll animations to run at 120Hz on 120Hz displays."
The issue cropped up quickly on user forums at MacRumors; the purported fix in Safari Technology Preview 135 was noted initially by 9to5 Mac.
First, a little background on how the issue has unfolded.
Last year, Apple introduced a major software change in support of the launch of its own M1 ARM-based silicon (The company is phasing out the use of Intel's x86 processors.) Programs running on the new ARM-based silicon relied on an emulation layer until developers could update their code. (An emulation layer simulates the x86 architecture, so the CPU, file system and system information functions are all virtualized.)
This year, on Oct. 18, Apple launched the new 14- and 16-in MacBook Pros running macOS Monterey. One of big features in the new laptops is a new Mini-LED-based display offering more vibrant colors and a 120Hz refresh rate through Apple's ProMotion adaptive technology.
ProMotion was initially launched in 2017 on the iPad Pro, and is now offered on the iPhone 13 Pro. The technology enabled adaptive refresh rates that would adjust to the responsiveness needed by applications. The promise ProMotion's 120Hz refresh rate on the new MacBook Pro was improved responsiveness and smoother scrolling.
After the MacBook Pro launch, however, it appeared that some front-line applications, including Apple's own Safari browser, didn't support the new refresh rate via ProMotion. Users began complaining that scrolling was running at 60Hz, creating a jerky experience when navigating through web pages. (ProMotion works for other features such as minimizing windows or moving them around the desktop.)
Apple's Safari Technology Preview is designed to provide users with an experimental version of the browser aimed at developers; their feedback weighs into what features the final version will have.
The release of the latest version of Safari Technology Preview prompted a new round of complaints from MacRumors users that the scrolling issue remains unfixed.
Because the process for vetting software updates via the Preview program will likely take time, it's unclear when the regular release version of Safari will get the changes designed to bring full ProMotion support.