https://bugs.kde.org/show_bug.cgi?id=521315
Bug ID: 521315
Summary: Launch feedback (busy cursor) is shown when an
already-run ning app activates its own existing
window via xdg-activation
Classification: Plasma
Product: kwin
Version First 6.6.4
Reported In:
Platform: Kubuntu
OS: Linux
Status: REPORTED
Severity: minor
Priority: NOR
Component: wayland-generic
Assignee: [email protected]
Reporter: [email protected]
Target Milestone: ---
SUMMARY
When an application requests activation of its own already-mapped window
through xdg-activation (e.g. Qt's QWidget::activateWindow()), KWin shows
app-launch feedback — the busy/bouncing cursor — even though nothing is
being launched. The activation itself works correctly; only the feedback
is wrong.
In src/xdgactivationv1.cpp, XdgActivationV1Integration::requestToken()
decides showNotify purely from the appId: feedback is shown whenever the
appId differs from the active window's desktopFileName and the app's
.desktop file doesn't set StartupNotify=false (default true). The
requesting surface is resolved at the top of the function
(waylandServer()->findWindow(surface)) but is not taken into account.
If the token request carries a surface that is already mapped, this is a
window-activation request, not an application launch, and startup
feedback should arguably be suppressed.
Real-world case: Telegram Desktop is adding window activation when a
touchpad swipe-to-reply gesture happens on an unfocused window
(https://github.com/telegramdesktop/tdesktop/pull/30797). Focus transfer
works, but every swipe flashes the busy cursor for the user.
STEPS TO REPRODUCE
1. Run any app whose .desktop file does not set StartupNotify=false
(the default), e.g. a Qt 6 app.
2. Focus a different application, keeping the first app's window visible.
3. Make the first app call QWidget::activateWindow() on its mapped window
in response to user input on its surface (so it holds a valid serial
and the token is granted).
OBSERVED RESULT
The window is activated (correct), and the busy-cursor launch feedback
flashes until the token is consumed (incorrect — no app is launching).
EXPECTED RESULT
No launch feedback when the activation token request comes from an
already-mapped surface; feedback only for actual launches.
WORKAROUND
Adding X-KDE-StartupNotify=false to the app's .desktop file suppresses
the cursor, but also disables legitimate launch feedback for that app.
SOFTWARE/OS VERSIONS
Operating System: Kubuntu 26.04
KDE Plasma Version: 6.6.4
KDE Frameworks Version: 6.10.2
Qt Version: 6.10.2 (client app: Qt's xdg-activation path in
QWidget::activateWindow())
Graphics Platform: Wayland
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