(I attached a video to show the bug, see below). I have been struggling with performance issues for a while now, before and after updating to 24. The timeline would become extremely slow, only when completely zoomed in would it be smooth. As soon as I zoomed out, it would freeze for several seconds, and the mac wheel would start spinning. I tried many things; resetting preferences, deleting cache, disabling 3rd party plugins, clean reinstall, moving scratch disks, deleting user workspaces, disabling AV headers/waveforms, moving everything to a new project; as many things as I could reasonably try while still needing to meet my deadlines. On a whim I tried disabling "Show duplicate frame markers", and suddenly everything is smooth again. I still have some "lagginess" when zooming in and out in the timeline, but it is now minimal and my projects are finally workable again. I saw a post from a year ago detailing the same issue, but I thought it would be appreciated to call attention to this bug now, and to help people who might have the same issues.  (The bug behaves the same way with A/V Headers and Names enabled, I disabled them for privacy.   1. Version 24.0.0 2. MacOS Sonoma     2022 Mac Studio M1 Ultra     Total 20 cores     64GB RAM     1 TB Harddrive, 800GB available (Project on internal harddrive)     2 TB External Samsung T7 SSD, 400GB available (Media files on external)     4 TB External Lacie SSD, 2,3 TB available (Media cache on external) 3. Enable "Show duplicate frame markers" and scroll/zoom in and out in the timeline. 4. Normal smooth performance expected, laggy and unresponsive/project freezing is actual result.   I hope this will help someone, and prevent users from having to go through the troubleshooting I did. Best regards, John ... View more