Our pure JavaScript Scheduler component


Post by Robert Hirst »

On the bigdataset demo, scrolling upwards using the mouse wheel is very sluggish when near the top of the list, although performance is fine when scrolling upwards further down the list.

Steps to reproduce:

1. Load the bigdataset demo
2. Turn the mouse wheel down one full turn
3. Count number of upward mouse turns required to return to the top of the list. For me, one down turn requires 3-5 upward turns to return to the start of the list.

Expected outcome:

I'd expect 1 turn down to only need 1 turn upwards to return to the start of the list. If you repeat the above but start already scrolled to have resource #50 at the top of the screen, one turn down, one turn up returns you to the same position as you started.

Affected browsers:

I've tested in Chrome 75 and Firefox 68.

Scheduler version tested:

Scheduler 2.2

Post by pmiklashevich »

We cannot reproduce your issue. Could you please follow the link https://www.bryntum.com/examples/scheduler/bigdataset/?video=1
scroll the way you described above and submit a report using the "Feedback" button at the right? Then we will get a video report and some extra details that might help to reproduce the issue. Also please mention here what OS you're using. Have you tried to perform the scroll using different devices (different mouses, touchpads, etc)? Do you use a mouse with infinite scroll wheel or it uses like "ticks" (small fixed steps) while scrolling?

Pavlo Miklashevych
Sr. Frontend Developer


Post by Robert Hirst »

Tried multiple mice. The mice I've tried it on have ticked scrolling. I've used the link to submit a video, I'm not sure if it worked though.

OS is Windows 10.

I've just tried it on a touchpad on bigdataset and it manifests slightly differently:

If you give it fast upwards swipe with two fingers from the top of the list, the scroll is smooth and glides gently to a stop.

Then if you repeat the same motion in an downwards direction, it starts to stutter near the top of the list.

Starting in the middle of the list, both up and down scrolls are smooth and glide gently to a halt.

Post by Maxim Gorkovsky »

Reproduced, ticket opened here: https://github.com/bryntum/support/issues/539
Thank you for report

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