1910088 - Clearing contenteditable element with negative margin within a shadowdom causes other elements to disapear

Status: NEW

(Core :: DOM: Editor, defect)

Description

[matthias]

Attachment: demo.html

User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:130.0) Gecko/20100101 Firefox/130.0

Steps to reproduce:

Clearing a contenteditable element (removing the text by either pressing crtl+x or pressing backspace/delete on the empty input), causes all other children of the same parent to disapear, if the parent element is set to display:flex only prior elements will disapear.

Multiple conditions are required for this to happen:

• the contenteditable element has to be part of a shadow dom
• the contenteditable element has negative margin
• other elements are only affected when the field is cleared with ctrl+x or the field is empty when attempting to delete text

Actual results:

Other elements disappear/get shifted by the amount of the negative margin

Expected results:

Nothing should disappear

Comment 1

[Francesco Lodolo [:flod]]

Please move if this is not the right product/component.

Comment 2

[Hsin-Yi Tsai (she/her) [:hsinyi]]

Hi Daniel,
I got this regression window - https://phabricator.services.mozilla.com/D187241
Can you please take a look? Thank you.

Comment 3

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

Set release status flags based on info from the regressing bug 1802466

Comment 4

[Donal Meehan [:dmeehan]]

:canadahonk, pinging as triage owner if this could be triaged for severity?

Comment 5

[Hsin-Yi Tsai (she/her) [:hsinyi]]

S3 particularly given that it requires several conditions. Daniel, please adjust if you have a different opinion.

Comment 6

[Daniel Holbert [:dholbert]]

I'm away for a couple weeks, but can take a look when I'm back.

I did take a quick look just to be sure I can reproduce the bug and can confirm the regression range (yes on both).

My steps to reproduce are:
(1) Load attached testcase ( https://bugzilla.mozilla.org/attachment.cgi?id=9416261 )
(2) Double-click the "asdf" text near the middle
(3) Press backspace.
EXPECTED RESULTS: Only asdf should disappear.
ACTUAL RESULTS: All of the text before asdf disappears as well.

Comment 7

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

Set release status flags based on info from the regressing bug 1802466