Overview

KeePass currently does not show in Alt+Tab under GNOME Wayland until StartupNotify (from the .desktop file) times out. I suspect this is because of the naming differences between the X11 WM_CLASS and Wayland/xdg-shell's app_id.

Under X11, I believe the Qt XCB platform plugin uses QCoreApplication::applicationName() to set the WM_CLASS property. KeePassXC's WM_CLASS is:

$ xprop WM_CLASS
WM_CLASS(STRING) = "keepassxc", "KeePassXC"

Under Wayland, qtwayland uses the .desktop filename to set the app_id: https://github.com/qt/qtwayland/blob/20d7cc45933a4a26c886b47c0b69da82195e7204/src/client/qwaylandwindow.cpp#L159-L163 Thus, the value is set to org.keepassxc.KeePassXC. This can be confirmed by using gnome-shell's "looking glass" feature:

Because KeePassXC's .desktop file specifies:

StartupWMClass=keepassxc

it will never match under a Wayland session.

Steps to Reproduce

1. Load Wayland gnome-shell session
2. Start KeePassXC via its .desktop file
3. Immediately try to Alt+Tab

Expected Behavior

KeePassXC should immediately show up in the Alt+Tab list.

Actual Behavior

KeePassXC is missing from Alt+Tab list until StartupNotify times out.

Context

KeePassXC - Version 2.6.4
Revision: 34a78f0

Qt 5.15.2
Debugging mode is disabled.

Operating system: Fedora 34 (Workstation Edition)
CPU architecture: x86_64
Kernel: linux 5.10.19-200.fc33.x86_64

Enabled extensions:
- Auto-Type
- Browser Integration
- SSH Agent
- KeeShare (signed and unsigned sharing)
- YubiKey
- Secret Service Integration

Cryptographic libraries:
- libgcrypt 1.9.2-unknown

Operating System: Fedora 34 (also reproducible under 33)
Desktop Env: Gnome
Windowing System: Wayland