It happens when you have scroll-behavior: smooth set on the viewport (html or body). Comment that line out and it will work normally. Dragging the native scrollbar up/down works fine. It's only when you try and drag the svrollbar up/down there is a noticeable lag.
Here's a REPL showing the bug https://svelte.dev/repl/30b4e8bbd90c4b8e97100a1225f5be66?version=3.48.0
It happens when you have
scroll-behavior: smooth
set on the viewport (html or body). Comment that line out and it will work normally. Dragging the native scrollbar up/down works fine. It's only when you try and drag the svrollbar up/down there is a noticeable lag.I've also included a video demo showing the issue svrollbar-smooth-scroll-bug.webm