After the release of macOS Tahoe, some developers noticed that Electron apps could overload the Mac's rendering system due to an incompatibility with the way these apps overrode the default window corner mask. Users experienced issues such as flickering while scrolling when interacting with any app (including those not based on Electron) while an Electron app window was visible on the desktop.
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Major Electron-based apps have since released updates to work around this bug, but that required waiting for updates from each developer of installed Electron apps. With the latest 26.2 betas, Apple has fixed the incompatibility at the system level.
The discovery was made by @Normarayr, who kept a list of all the problematic Electron apps that were causing this issue. Once users update to 26.2, this list will become useless as the rendering system will no longer be overloaded in this way.
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The issue stemmed from Electron apps using a private AppKit API in an undocumented way. The use of private APIs is strongly discouraged by Apple and is prohibited in the iOS App Store app rules, as it can lead to issues like this.
Rather than wait for all Electron apps to resolve the issue, Apple stepped in and implemented a fundamental fix in Tahoe 26.2 that prevents any app from affecting the system in this way in the future.
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macOS Tahoe 26.2 is currently in developer beta and is expected to be available to all users in December. In addition to performance and stability improvements, macOS 26.2 will introduce a new Edge Light to enhance camera lighting and higher-performance Thunderbolt 5 connections for using multiple Macs in a cluster.
