macOS Tahoe apps using outdated Electron versions can cause diminished system performance. The latest version of Local is still using Electron 37.2.6.
Bump Electron to at least versions v38.2.0 or v37.6.0.
See: Shamelectron - Electron Apps macOS Tahoe GPU Performance Tracker or fix: MacOS 26 Tahoe - stop overriding private cornerMask API to fix WindowServer GPU load by avarayr · Pull Request #48376 · electron/electron · GitHub
Thanks for the heads up @scottbuscemi – I haven’t taken the jump to Tahoe yet, have you? Is Local noticeably slower?
If you do notice some slowness, where do you see it? For example, is it doing things in the Local app, like clicking and navigating, or does it seem to also affect how you click and navigate within the WP-admin?
From the PR you link to, it seems like it would be for Electron, but it’s hard to verify without upgrading from Sequoia.
We have a ticket in our backlog to upgrade to a newer LTS version of Electron soon, but I don’t have a firm ETA for when.
There’s a good explanation of the effects here: GitHub · Where software is built
Using an M1 Max MacBook Pro, having Electron-based apps open / not minimized causes a huge lag.
CPU and GPU usage remains low, but if I have Discord and VS Code open, moving windows, scrolling is stuttery. It happens even when only Discord is open but it gets worse if I open a second Electron app.
This is kind of weird because while having Discord open and I’m in Chrome, the lag still occurs, but it’s fixed if I minimize Discord (even though Chrome is fully in focus and maximized). This happens since upgrading to macOS 26 RC, macOS 15 didn’t have this issue.
There is a similar lag if I open Settings - Wallpapers, moving the Settings window is laggy then (looks like 60fps instead of 120).
tl;dr If the Local app window is “open” and not minimized/hidden, then it will severely slow down overall system performance due to excessive GPU calculations.
Thank you for sharing that @scottbuscemi!
Our next release is going to bump Electron to v37.5.1, but our team already has a ticket in and work being planned to get things updated up to v37.6+ soon. So stay tuned and we’ll keep you posted! 
Thanks for the update. The performance implications are quite rough - even if the window isn’t in view of the screen. I’d recommend macOS Tahoe users close the Local window when not needed in the meantime.
Thank you for your patience and communication with us on this @scottbuscemi!