Created attachment 425732 [details] Screencast of the issue Safari Stable Version 14.0.3 (15610.4.3.1.7, 15610) Safari Technology Preview Release 123 (Safari 14.2, WebKit 15612.1.7.10) macOS 10.15.7 and macOS 11.2.3 Steps to reproduce: 1.) Make sure in System Settings that scroll bars are shown automatically based on input device 2.) Visit a long page with a scroll bar 3.) scroll -> result: Thin scroll bar appears -> OKAY! 4.) Move the mouse cursor to the position of the scroll bar / Track 5.) scroll -> Result wide Track and wide scroll bar appears -> OKAY! 6.) repeat steps 3,4,5 Actual: When you repeat steps 3,4,5 the Track and the scroll bar do not behave as expected. The track and scrollbar is thinner when you the mouse cursor is over the area of the scrollbar/track. The scroll bar is wider when you scroll through the page when the mouse cusror is in the area of the page. Expected: When the mouse cursor is not over the scrollbar/track area, the scroll bar should be thin. When the mouse cursor is over the scrollbar/track area, the scroll bar and track should be wide. A screencast is attached. Thanks for checking.
<rdar://problem/76548655>
Update: Still an issue in Safari Version 16.5 (17615.2.9.11.6, 17615) on macOS 12.6.6.