1553366 - glitch when cursor changes from zoom-in to pointer

Status: UNCONFIRMED

(Core :: DOM: UI Events & Focus Handling, defect, P3)

Description

[Marcel Dejean]

Attachment: cursor glitch

User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:68.0) Gecko/20100101 Firefox/68.0

Steps to reproduce:

move cursor across this page:

https://www.flickr.com/photos/mtacc-esa/33665905848/in/photostream/

nightly 69.0a1 20190521214552 win32

Actual results:

graphical glitch as the cursor changes from zoom-in to pointer

Comment 1

[Timea Cernea [:tbabos][inactive]]

Hi Marcel,

Is this issue something new in Nightly or it is reproducible in other firefox versions (Beta and Release)?
I didn't manage to reproduce this on Windows 10 x64, might be specific to win32 tho.

Comment 2

[Marcel Dejean]

OS is windows 7 x64. Sorry for not specifying that. It occurs in both 64 and 32 bit builds. It occurs in release. I attempted to bisect, but it occurs even in Firefox 28, and the site does not work on earlier versions.

Comment 3

[Marcel Dejean]

Attachment: test.html

After some poking i've managed to come up with a simpler testcase. With this I tried to bisect. The bug becomes much rarer before 2014-05-27 (only happens on some mouseovers for the testcase, though much more frequently on the actual website), but I've managed to trigger it even in Firefox 1.0.

Comment 4

[Timea Cernea [:tbabos][inactive]]

Tried the site and the reduced testcase on Windows 7 x64 but I can't reproduce this.

What it would be worth trying out:

• Check if this is also reproducible in Chrome - just to be sure it is not due to some system error
• Try to reproduce this using a new profile or safe mode, this is to ensure that there are no custom settings or add-ons that could be the cause of the issue

Safe mode: https://support.mozilla.org/en-US/kb/troubleshoot-firefox-issues-using-safe-mode.
New Clean Profile: https://support.mozilla.org/en-US/kb/profile-manager-create-and-remove-firefox-profiles

Comment 5

[Marcel Dejean]

It does not occur in Chrome. It does occur with a blank new profile.

Comment 6

[Timea Cernea [:tbabos][inactive]]

Still can't reproduce it on my end but moving it over to a component so developers might have a better idea of what is going on.

Comment 7

[Dante]

Attachment: glitch.html

I'm also experiencing this issue. I noticed it on Github's website.

Steps to reproduce:

1. Go to a merged pull request on Github (for instance this random one: https://github.com/mozilla/pdf.js/pull/14803, but any merged one will do).
2. Move your mouse back and forth over the copy icon and the date (below the PR title).
3. Cursor/pointer should glitch when entering the copy icon.

I also simple test case which works in only css as opposed to using js like the other one. Div #1 glitches the most (almost every time for me). You need to hover over the text and then move the mouse to the white box to summon the glitch.

Observations: the glitch...

• Happens when the cursor changes from any type into a selection of cursor types (including pointer and wait, but not cell, grab or zoom-in). Not only from zoom-in to pointer.
• Happens regardless of windows display scaling.
• Is hard to reproduce on a high refresh rate monitor. It is still possible, but you need to move the mouse rather quickly and it does not always happen.
• Does not occur in Edge or Internet Explorer (yes I tested IE).
• Does not occur when OBS is running and capturing the browser window with capture method "Windows Graphics Capture (Windows 10 1903 and up)". (with other capture methods the glitch happens but isn't captured by OBS)
• Does not occur with the "Windows Black (system scheme)" or inverted scheme, but it does happen with magnified or "Windows Standard (large)". (set in mouse properties)
• Does not occur with pointer trails enabled. (also in mouse properties)
• My glitched cursor looks slightly different to the one in the picture: it is white/yellow and green (as opposed to yellow and magenta) and about 2.5x as large as the normal cursor. It is enlarged from the top-left corner, growing down and right.

Some system information:
User-agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:99.0) Gecko/20100101 Firefox/99.0
OS: Windows_NT 10.0 19044
Graphics card: NVIDIA GeForce GTX 1060 6GB, driver version 27.21.14.6140

Comment 8

[Dante]

I just managed to reproduce the glitch outside of Firefox, so it's not only a Firefox bug.
I suspect it's caused by the cursor changing shape too often too quickly.

General steps to reproduce anywhere in Windows:

1. Find a place where the cursor goes between multiple transitions. For example a window that has text cursor (almost) until the border, with a default cursor behind the window. (you automatically get the resize cursor in-between)
2. Move mouse rapidly back and forth across the transition.
3. Cursor should glitch going across the transition.

An example of where this happens is when moving the cursor in an explorer window from the search bar to the part between it and the address bar.
I managed to reproduce this with Sublime Text, Windows Explorer, notepad, Windows 10 settings, and even the taskbar (taskbar unlocked).

So this also happens outside of Firefox, but still Firefox is the only browser that shows this glitch within a window.