Steps to reproduce:

Go on https://hebdo.framapad.org/p/e6bm8nrezero0th-9azef using firefox nightly (97 - 2022-01-06).

Put the cursor at the end of line 59. Write some letters, and use backspace to delete them.

Actual results:

Firefox becomes unresponsive.

Expected results:

Firefox not freezing.

It seems the issue comes from mozilla::a11y::EventQueue::CoalesceEvents. See profile attached.

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

(In reply to Chocobozzz from comment #0)

It seems the issue comes from mozilla::a11y::EventQueue::CoalesceEvents. See profile attached.

See https://share.firefox.dev/3HMSVMB

Disability Access APIs seems a proper component.

Thanks for the report.
When you say Firefox becomes unresponsive, is this a hang for a period of time or does it go unresponsive forever (requiring a force kill)?
Do you know whether this is a recent issue; i.e. is this the first Firefox build where you've tried this page or have you tried this in the past and it worked before but doesn't now?

I'm wondering whether this might have been caused by the fix for bug 1613634.

(In reply to James Teh [:Jamie] from comment #3)

Thanks for the report.

Hi!

When you say Firefox becomes unresponsive, is this a hang for a period of time or does it go unresponsive forever (requiring a force kill)?

It depends how many backspaces you pressed :) With 2 backspaces firefox becomes unresponsive during ~8 seconds on my computer. With more backspaces, it takes so much time that have to kill the tab.

Do you know whether this is a recent issue; i.e. is this the first Firefox build where you've tried this page or have you tried this in the past and it worked before but doesn't now?

Unfortunately I don't know when this bug started because it happens only on pads having a specific structure. I just tested using Firefox ESR (91) and the bug is still there. I also retested using nightly 2022-01-09 with the same result.

I'm wondering whether this might have been caused by the fix for bug 1613634.

Since I initially had the bug using firefox developer edition (96) I don't think it's related to this fix.

Adding another reproducing website because the one pasted in the original message expired: https://annuel2.framapad.org/p/azzega

I experience freezes in contenteditable too, but I don't think it's related to the spellcheck attribute. I can turn off spellcheck and it still freezes. I experience this on Reddit and Gizmodo.

Matt, I'm wondering whether you're seeing bug 1800028 rather than this one. I'll update that bug with some questions and CC you.