2013721 - Highlight text selection is slow/inconsistent when Windows 11 taskbar is hidden.

Status: ASSIGNED

(Core :: DOM: Selection, defect, P3)

Description

[PWN3D_]

User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:147.0) Gecko/20100101 Firefox/147.0

Steps to reproduce:

While having Windows 11 taskbar auto-hide, and Firefox is on full screen or at least is the window border is touching the bottom of the screen, while highlighting a long text and going down a page. The text must be long enough to make the scrollbar going down the page while selecting text.

Actual results:

The speed of the selection will be way slower/jerky than normal.

Expected results:

The speed should be the same as with Windows 11 taskbar visible or firefox being windowed and not touching the bottom of the screen with taskbar hidden.

This behavior doesn't happen on any chromium based browser.

Someone already have noticed it few years ago : https://www.reddit.com/r/firefox/comments/1851sld/how_to_change_scrolling_by_highlighting_behaviour/

Comment 1

[BugBot [:suhaib / :marco/ :calixte]]

The Bugbug bot thinks this bug should belong to the 'Core::DOM: Selection' component, and is moving the bug to that component. Please correct in case you think the bot is wrong.

Comment 2

[Olli Pettay [:smaug][[e-mail]]]

I can't on top of my head remember where the autoscrolling for selection is implemented. Can you remember (and perhaps move this to a better component if needed.)

Comment 3

[Jan Jaeschke [:jjaschke]]

I only tested on Linux, and I interpret "Firefox is on full screen or at least is the window border is touching the bottom of the screen" as maximized window / window is at bottom position of the screen, not fullscreen (F11) mode.

I can confirm that the scroll speed is much slower in that case. It seems that Chromium uses a "hot zone" of 20ish pixels at the edge of the viewport in which they start scrolling, and their adaptive scroll speed starts from there. I'll try to create a patch...

Comment 4

[Keith Cirkel [:keithamus]]

(Small/Trivial) minor significance, cosmetic issues, low or no impact to users

Comment 5

[Jan Jaeschke [:jjaschke]]

Attachment: Bug 2013721 - Speed up auto-scrolling by introducing hotzone at edge of scroller. r=emilio!