[Bug 60050] New: winewayland: Alt without Ctrl is mapped to AltGr, breaking Alt+<letter> menu mnemonics on layouts that have AltGr (AZERTY, QWERTZ, …)

[WineHQ Bugzilla]

http://bugs.winehq.org/show_bug.cgi?id=60050

            Bug ID: 60050
           Summary: winewayland: Alt without Ctrl is mapped to AltGr,
                    breaking Alt+<letter> menu mnemonics on layouts that
                    have AltGr (AZERTY, QWERTZ, …)
           Product: Wine
           Version: 11.13
          Hardware: x86-64
                OS: Linux
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: winewayland
          Assignee: [e-mail]
          Reporter: [e-mail]
  Target Milestone: ---
      Distribution: ---

Under the Wayland driver (winewayland), pressing Alt+<letter> does not trigger
the corresponding menu mnemonic on any keyboard layout that has an AltGr key
(e.g. French AZERTY, German QWERTZ). For example, in Notepad on a French
layout,
**Alt+F does not open the "Fichier" menu**; the keystroke produces no usable
WM_SYSCHAR. The same applies to the other Alt+<letter> mnemonics (Alt+E, Alt+O,
…).

This makes Alt+<letter> menu access unusable for a large class of applications
on the most common non-US European layouts.

The X11 driver (winex11) does not have this problem: Alt+<letter> opens the
mnemonic as expected.

(Note: this is specific to Alt+<letter>. Tapping Alt alone to enter menu mode,
and F10 menu navigation, are unaffected — they do not go through the character
table.)

Steps to reproduce

1. Run a Wayland session with an AltGr layout (e.g. French/AZERTY or
German/QWERTZ).
2. Make Wine use the Wayland driver:
   `wine reg add "HKCU\Software\Wine\Drivers" /v Graphics /d "wayland,x11" /f`
3. `wine notepad`
4. Press "Alt+F" (left Alt).

Expected: the "File"/"Fichier" menu drops down (mnemonic match).
Actual: nothing happens; the menu does not open. Same for Alt+E, Alt+O, etc.

Confirmed on stock Wine 11.13 (winewayland, French/AZERTY compositor keymap).
The offending code is present unchanged in current git master
(dlls/winewayland.drv/wayland_keyboard.c).

Root cause

In `add_xkb_layout()` (dlls/winewayland.drv/wayland_keyboard.c), while building
the VK_TO_WCHARS table, the loop over modifier combinations maps *any*
combination that contains the Alt bit to the XKB AltGr mask:


for (mod = 0; mod < 8; ++mod)
{
    ...
    if (mod & (1 << 0)) mod_mask |= shift_mask;
    if (mod & (1 << 1)) mod_mask |= control_mask;
    /* Windows uses VK_CTRL + VK_MENU for AltGr, we cannot combine Ctrl and Alt
*/
    if (mod & (1 << 2)) mod_mask = (mod_mask & ~control_mask) | altgr_mask;
    ...
}

Bit 2 is the Alt (VK_MENU) modifier. The problem is that this also fires for
Alt alone (bit 2 set, bit 1 / Ctrl clear). On Windows, AltGr is `VK_CONTROL +
VK_MENU`; Alt on its own is *not* a layout modifier and must produce the same
glyph as the base column, so that Alt+<letter> yields WM_SYSCHAR with the plain
letter and application menus can match their mnemonics.

By mapping Alt-alone to the AltGr mask, the layout table returns the
AltGr-column
glyph (which is empty for most letters) for Alt+<letter>, so no usable
WM_SYSCHAR
is produced and the mnemonic never matches.

Proposed fix

Only map to AltGr when *both* the Ctrl bit and the Alt bit are set (i.e.
Ctrl+Alt, and Shift+Ctrl+Alt); Alt alone keeps the base column:

```diff
-            /* Windows uses VK_CTRL + VK_MENU for AltGr, we cannot combine
Ctrl and Alt */
-            if (mod & (1 << 2)) mod_mask = (mod_mask & ~control_mask) |
altgr_mask;
+            /* Windows uses VK_CTRL + VK_MENU for AltGr, we cannot combine
Ctrl and Alt.
+             * Alt alone (without Ctrl) is not a layout modifier on Windows:
it must
+             * produce the base-column glyph so Alt+<letter> yields WM_SYSCHAR
with the
+             * plain letter and menu mnemonics match. Only Ctrl+Alt (and
Shift+Ctrl+Alt)
+             * maps to the XKB AltGr mask. */
+            if ((mod & (1 << 2)) && (mod & (1 << 1)))
+                mod_mask = (mod_mask & ~control_mask) | altgr_mask;
```

-- 
Do not reply to this email, post in Bugzilla using the
above URL to reply.
You are receiving this mail because:
You are watching all bug changes.