Created attachment 466777 [details] Minimal reproduction showing the bug. Red area is not visible when opened in Chrome or FF. When creating a scrolling container with "overflow: scroll; display: flex; padding: 10px" and adding a child node with "flex-grow: 1; margin: -10px", Safari allows the user to scroll horizontally, where Chrome and FF don't. The attachment contains a minimal reproduction. It should show how in Safari the green "Content" overflows on the x-axis, although its width should not be larger than its parent's width. Next to Safari 16, this behavior can also be observed with the build 265350@main from JUNE 21, 2023 AT 02:27 PM GMT+2. The closest I could find was https://bugs.webkit.org/show_bug.cgi?id=218579.
Created attachment 466788 [details] rendering in safari, firefox, edge, chrome So I can't reproduce with Safari Version 17.0 (19616.1.18) with 265385@main JUNE 22, 2023 AT 11:10 AM GMT+9 https://webkit.org/build-archives/#mac-ventura-x86_64%20arm64
ha sorry, you need to scroll. Indeed I can reproduce once scrolling.
Created attachment 466789 [details] after scrolling rendering in safari, firefox, edge, chrome
<rdar://problem/111137750>