1768147 - contextmenu MouseEvent triggered by a ContextMenu key press uses bottom left corner in right-to-left (RTL)

Status: NEW

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

Description

[Henry Wilkes (they/them) [:henry-x]]

Attachment: right-to-left context menu opened with key press

Steps to reproduce:

1. Open a right-to-left document with a focusable element.
2. Tab to focus the element.
3. Press the "ContextMenu" key (https://en.wikipedia.org/wiki/Menu_key).

Result

The context menu opens with the top right corner touching the bottom left corner of the focused element. As such, the context menu is not below the focused element. See the attachment.

Expect

The context menu opens with the top right corner touching the bottom right corner of the focused element. I.e. the reverse of the left-to-right display so that the context menu appears below the focused element.

I think the problem is that the "contextmenu" MouseEvent has its clientX/screenX always set using the bottom left of the focused element, without taking the direction of the element into account. I think it is set here https://searchfox.org/mozilla-central/rev/408eac3ccaea2d35b00706925d4d944803e19aba/layout/base/PresShell.cpp#8839 but I'm not sure.

Comment 1

[Emilio Cobos Álvarez (:emilio)]

It's https://searchfox.org/mozilla-central/rev/408eac3ccaea2d35b00706925d4d944803e19aba/layout/base/PresShell.cpp#9153. That probably needs a + width.

Comment 2

[Masayuki Nakano [:masayuki] (he/him)(JST, +0900)(away 4/27 - 5/6)]

Must be annoying bug for RTL language users, but the symptom is not so serious, so setting normal priority and severity.