SUMMARY Before 9f8b8c97[1] it was possible to use layer-shell-qt with only `QT_WAYLAND_SHELL_INTEGRATION=layer-shell`. Existing code with QWindow->setScreen() was assigning the screens without any changes. Now any application that uses multiple screens MUST use layer-shell-qt explicitly and implement an additional, ifdef'ed code path to set the screens for only that scenario. And by the way, layer-shell-qt lacks the way to check if wlr-layer-shell is actually supported by the compositor, which makes that code path even more complicated. For the record, I perfectly realize the purpose of desiredScreen -- lack of the way to request a compositor default screen with setScreen. I don't have a good solution for that, just a random idea to throw at you: Can we set primaryScreen to QPlaceholderPlatformScreen from layer-shell-qt init code or otherwise keep it in sync with the compositor default? Are there other, better ways to check that the window's screen was set explicitly by user? [1]: https://invent.kde.org/plasma/layer-shell-qt/-/merge_requests/15 STEPS TO REPRODUCE ``` for (QScreen *screen : qGuiApp->primaryScreen()->virtualSiblings()) { QQuickView *view = new QQuickView(); // ... view->setScreen(screen); view->setResizeMode(QQuickView::SizeRootObjectToView); view->setGeometry(screen->geometry()); view->show(); } ``` (if this code looks familiar - yes, it's a simplified snippet from sddm GreeterApp) OBSERVED RESULT All the surfaces are created on the same screen, only one is visible. EXPECTED RESULT I expect to see one surface per screen. SOFTWARE/OS VERSIONS Qt Version: 5.15.5 Layer-shell-qt version: 5.25.4 ADDITIONAL INFORMATION