HTML5 Mouse Wheel messes up frame timing, serious slow down

[twilson90]

The bug appears to have been introduced around this commit:
e85da87

Using the mousewheel messes with the frame timing for a second or so after each mousehweel event.
With each refresh the severity of the bad frame timing can vary.

In Chrome's perfomance profiler it shows a load of 'partially presented frames' when this occurs, I've uploaded a copy of the profiler dump:

Trace-20260629T122706.json.gz

Video:

Test.-.Google.Chrome.2026-06-29.12-32-56.mp4

Just observe the frame time graph in the video to see a demonstration of what's happening.

As far as I can tell it's only the mousewheel that has this effect. Other input events are fine.
And it appears to only affect the HTML5 target.

[dimensionscape]

Hmm, wheel events are tied into chrome’s scrolling/compositor pipeline, so they can perturb RAF scheduling more than other input events. I will restore the prior RAF pacing.

[dimensionscape]

Can you confirm if this is resolved with the latest commits?

[twilson90]

Yes, I think that did the trick. Thanks!