1299875 - Invalid altKey attribute of the keydown event when typing a character with AltGr

Status: RESOLVED WORKSFORME

(Core :: Widget: Win32, defect)

Description

[Tomasz P. Szynalski]

1. Go to http://unixpapa.com/js/testkey.html
2. Enable "modifiers".
3. Switch to a keyboard layout that uses key combinations with AltGr, e.g. Polish Programmers, US International, German etc.
4. Type AltGr+E (or another bound AltGr combo).
5. Notice that, for the keydown event for the E keystroke, the altKey and ctrlKey attributes are both false.

If you type an AltGr combo that's not used in the current layout, the altKey and ctrlKey attributes are both set to true, as they should be. (ctrlKey should be true because on Windows, AltGr is implemented as RAlt+LControl).

This is a new bug that breaks sites that use keyboard shortcuts with the Alt modifier key.

Comment 1

[Tooru Fujisawa [:arai]]

Confirmed the issue on Windows 7 32bit, Polish Programmers keyboard layout.

here's regression range:
https://hg.mozilla.org/integration/mozilla-inbound/pushloghtml?fromchange=dd12327c3e0c9f21326236ab8843f6f934579490&tochange=6ef9818a44c721778263259641de8259f443d765

looks like it's from bug 1154183.


Then, it's fixed in the following range:

https://hg.mozilla.org/mozilla-central/pushloghtml?fromchange=fc4a79cf9ac9681bfbeafb60f0056153b780e99e&tochange=3ba5426a03b495b6417fffb872d42874edb80855

maybe from bug 1293505?.


Tomasz, can you check if it's also fixed on nightly for you?

Comment 2

[Masayuki Nakano [:masayuki] (he/him)(JST, +0900)]

Um, this should be a long standing bug.

TextEditor (nsPlaintextEditor) doesn't handle keypress events whose Ctrl or Alt state is true as text input.  Therefore, we used to remove Alt/Ctrl key state in widget when the key press causes some text input.
https://dxr.mozilla.org/mozilla-central/rev/dbe4b47941c7b3d6298a0ead5e40dd828096c808/widget/windows/KeyboardLayout.cpp#567,582,589-590

Instead, WidgetKeyboardEvent should have a flag indicating if it's a printable event.

On the other hand, web pages can retrieve if "AltGraph" is active with KeyboardEvent.getModifierState().
https://developer.mozilla.org/en-US/docs/Web/API/KeyboardEvent/getModifierState

Although, the hack was applied only for keypress but applied for keydown too after bug 1154183?

Comment 3

[Tomasz P. Szynalski]

@arai
Yep, it is fixed in the current Nightly. Thank you for looking into it.

Comment 4

[Jim Mathies [:jimm]]

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