After macOS Tahoe launched, you may have noticed odd stutters while scrolling or switching between apps. The cause traced back to certain Electron apps. They overrode the default window corner mask in a way that pushed the Mac rendering system too hard. As long as one of these apps stayed visible on your desktop, performance across the system took a hit. Even apps that had nothing to do with Electron started to feel slow.
At first, the fix depended on the developers of each affected app. They released updates to limit the damage, yet that approach forced you to wait and hope every app on your Mac received attention. This created a messy situation. You faced uneven performance, even on well-maintained systems, and the root problem stayed in place.
How the issue came to light
The problem gained wider attention when @Normarayr started tracking the Electron apps linked to the slowdown. That list helped users understand which apps triggered the trouble. However, it also revealed the extent of the issue. Electron apps had been using a private AppKit API in a way Apple never documented or endorsed. Such practices break basic system rules and create risks for you and your workflow.
Due to this misuse, the normal rendering logic struggled to keep up. Apple discourages private API use for a reason. It disrupts stability, and in this case, it caused system-wide performance drops that no regular setting could fix.
Apple steps in with a system fix
With macOS Tahoe 26.2, Apple chose direct action. Instead of waiting for every Electron app to clean up its code, the update blocks any app from stressing the rendering system in this way. You get smoother scrolling, steadier window movement, and normal performance again, even if older Electron apps remain installed.
This change arrives as part of the 26.2 developer beta and heads to all users soon. Alongside this fix, Apple adds Edge Light to boost webcam lighting and improves Thunderbolt 5 performance for multi-Mac setups. As a result, your Mac runs more reliably, and you spend less time fighting slowdowns and more time getting real work done.
