2008841 - Dragging an element to the bottom of a reorderable moz-box-group causes a scroll bar to appear and flicker

Status: RESOLVED FIXED

(Toolkit :: UI Widgets, defect, P3)

Description

[Mark Banner (:standard8)]

STR

1. Visit https://firefoxux.github.io/firefox-desktop-components/?path=/story/ui-widgets-box-group--reorderable (I don't think we have a widget that's accessible in the current nightly Firefox UI).
2. Select the dots next to the first element.
3. Drag down to the bottom of the list, slowing down as you get to the last item.
4. Observe the list

Actual Results

When the blue line gets to be displayed at the bottom of the list, a scroll bar appears on the right. If the mouse is moved within the bottom quarter(ish) of the last element, then the scrollbar and list flicker as the scrollbar is hidden and re-shown.

Expected Results

No scrollbar appears, and no flickering.

Comment 1

[Mark Banner (:standard8)]

I noticed this when testing out bug 1972071, it is slightly worse if the moz-box-group is scrollable as well.

Comment 2

[Mark Banner (:standard8)]

Attachment: Bug 2008841 - Adjust the moz-reorderable-list drag indicator so that it does not extend beyond the bottom of the box area. r?#reusable-components-reviewers-rotation!

This avoids causing flickering of the scrollbar when dragging the item to the bottom of the list.

Comment 3

[Pulsebot]

Pushed by [e-mail]:
https://github.com/mozilla-firefox/firefox/commit/c9c7dcf8723d
https://hg.mozilla.org/integration/autoland/rev/1c770f8d2004
Adjust the moz-reorderable-list drag indicator so that it does not extend beyond the bottom of the box area. r=mkennedy

Comment 4

[Serban Stanca [:SerbanS]]

https://hg.mozilla.org/mozilla-central/rev/1c770f8d2004