1831753 - Incorrect behavior when selecting text with the mouse in macOS

Status: UNCONFIRMED

(Core :: DOM: UI Events & Focus Handling, enhancement)

Description

[5silentrain]

User Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:109.0) Gecko/20100101 Firefox/112.0

Steps to reproduce:

1. Open any site where you can select text (for example https://html5test.com/)
2. By holding the LMB, start selecting any text on the page. For example, repeat the selection of the text shown in this screenshot (from right to left): https://i.imgur.com/Tx4hR49.png
3. After you make a selection with the mouse from right to left, as shown in the screenshot above, release LMB to stop the selection.
4. Hold down the Shift key on your keyboard and click once with LMB outside of the previously selected text on the right side, as shown in this screenshot: https://i.imgur.com/bWD6L5N.png

Actual results:

Windows-style text selection will occur, but not macOS-style. See screenshot: https://i.imgur.com/Cw27CA8.png

Open Safari or Chrome and repeat the steps above. The result will be completely different! Here's what happens in Safari and Chrome:
https://i.imgur.com/lMM40fW.png
https://i.imgur.com/0za0sXB.png

Comment 1

[5silentrain]

Attachment: Selection in FF (step 1).png

Comment 2

[5silentrain]

Attachment: Selection in FF (step 2).png

Comment 3

[5silentrain]

Attachment: Selection in FF (result).png

Comment 4

[5silentrain]

Attachment: Selection in Safari (result).png

Comment 5

[5silentrain]

Attachment: Selection in Chrome (result).png

Comment 6

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

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

Comment 7

[5silentrain]

Can anyone confirm this please? 🙏

Comment 8

[5silentrain]

The problem with incorrect text selection is still present in the latest versions of Firefox:
Firefox 117.0.1
Firefox Developer Edition 118.0b9

I ask the developers to confirm the presence of this bug.