1552399 - Scrolling is extremely slow with keyboard. And pages continue to scroll without user interaction

Status: RESOLVED WORKSFORME

(Core :: Layout: Scrolling and Overflow, defect, P3)

Description

[Alice0775 White]

Attachment: about:support

Scrolling is extremely slow with keyboard.
And pages continue to scroll without user interaction after scroll a bit.

Reproducible: always

Steps To Reproduce 1:

1. Open hhttps://www.kepco.co.jp/energy_supply/supply/kaminari-info/index.html
2. Try scroll with keyboard down-arrow and up-arrow key
   ---- observe, scroll speed --- BUG
3. Do nothing and observe
   ---- observe, pages continue to scroll without user interaction --- BUG

Steps To Reproduce 2:

1. Open https://www.kepco.co.jp/energy_supply/supply/kaminari-info/index.html
2. Try scroll with mouse wheel or scroll bar
3. Do nothing and observe
   ---- observe, pages continue to scroll without user interaction --- BUG

Actual Results:
Scrolling is extremely slow using arrow key.
And pages continue to scroll without user interaction.

Expected Results:
Should be normal like Firefox66

Regression window:
https://hg.mozilla.org/integration/mozilla-inbound/pushloghtml?fromchange=f8b8346df03cfd7d683faf16ddded0afd528570b&tochange=893f2ec05d7acf999174e200b042c3c9ef6fdd7c

Regressed by:
893f2ec05d7acf999174e200b042c3c9ef6fdd7c Ryan Hunt — Bug 1519553 - Don't round scroll anchor adjustments to device pixels. r=dholbert

Ryan, Your patch seems to cause the regression. Can you please look into this?

Comment 1

[Alice0775 White]

Attachment: archive zip (For the record)

Comment 3

[Daniel Holbert [:dholbert]]

I can reproduce on Linux (using a Dell 24" monitor which is not high-DPI, just in case that matters for reproducibility).

I was not able to reproduce on a different linux machine that has 200%-scaling HiDPI applied (a Dell XPS 15" laptop). So, this might only be easy to reproduce at "native"/100% pixel scaling (or therabouts)

Also noteworthy: I tested Chrome 76 dev edition on the first machine where I easily see the bug, and it does not trigger this bug -- scrolling seems fine there. (I don't see either of the unexpected "Actual Results" symptoms from comment 0.)

Comment 4

[Ryan Hunt [:rhunt] (on leave until early May)]

I won't have time to look at this anytime soon, unfortunately.

Comment 5

[Emilio Cobos Álvarez (:emilio)]

The keyboard scrolling is not an issue after bug 1554572. However in the archive the jittering still persists even after bug 1543599.

Comment 6

[Liz Henry (:lizzard) (relman/hg->git project)]

Happy to take a patch for 70 or beyond.
Since we are getting close to the end of the 69 beta cycle and this is set to P3, I'm marking it fix-optional for 69 and 70 to remove it from weekly triage.

Comment 7

[Emilio Cobos Álvarez (:emilio)]

This looks fixed now, probably by bug 1561450 or such.