After macOS Tahoe launched, some intrepid developers noticed that Electron apps could cause the Mac’s rendering system to be overloaded due to an incompatibility with the way Electron apps were overriding the default window corner mask. Users would experience issues like stuttery scrolling when interacting with any app (including non-Electron ones), as long as an Electron app window was currently visible on the desktop.
Major Electron-based apps have subsequently released software updates to work around this bug, but this meant waiting for an update from the developer of each Electron app installed on your Mac. With the latest 26.2 betas, Apple has now fixed the incompatibility at a system-wide level.
The discovery was noticed by @Normarayr, who had been maintaining a list of all the problematic Electron apps that could cause this issue. Once users update to 26.2, this list will become obsolete as the rendering system will no longer be able to overloaded in this way.
The origin of the issue was due to Electron apps fiddling with a private AppKit API in an undocumented matter. Private API usage is highly discouraged by Apple (and outlawed altogether in the rules for apps in the iOS App Store) precisely because it can lead to problems like this one.
But rather than wait for all Electron apps to clean up their own mess, Apple seems to have intervened and implemented a foundational fix in Tahoe 26.2 that prevents any app from affecting the system in this manner going forward.
macOS Tahoe 26.2 is currently in developer beta. It is expected to be released for all users in December. As well as performance and stability improvements, macOS 26.2 will add a new Edge Light feature to improve webcam illumination and higher performance Thunderbolt 5 interconnects for using multiple Macs in a cluster.
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