From 0759138c9cf395bbc3ef227560e2cb8a64b55dd1 Mon Sep 17 00:00:00 2001
From: Aleix Pol <aleixpol@kde.org>
Date: Thu, 11 Sep 2025 00:57:44 +0200
Subject: [PATCH] Window: Ensure we integrate windows that were already were
 shown in a different shell

---
 src/interfaces/window.cpp | 43 +++++++++++++++++++++++----------------
 src/interfaces/window.h   |  2 ++
 2 files changed, 27 insertions(+), 18 deletions(-)

diff --git a/src/interfaces/window.cpp b/src/interfaces/window.cpp
index e2635f1..e903d00 100644
--- a/src/interfaces/window.cpp
+++ b/src/interfaces/window.cpp
@@ -187,6 +187,9 @@ Window::Window(QWindow *window)
 {
     s_map.insert(d->parentWindow, this);
     window->installEventFilter(this);
+    if (window->handle()) {
+        qCWarning(LAYERSHELLQT) << d->parentWindow << "already has a shell integration. Call QWindow::close() first and show it again.";
+    }
 }
 
 bool Window::eventFilter(QObject *watched, QEvent *event)
@@ -196,28 +199,32 @@ bool Window::eventFilter(QObject *watched, QEvent *event)
         return false;
     }
     if (event->type() == QEvent::PlatformSurface) {
-        auto waylandWindow = dynamic_cast<QtWaylandClient::QWaylandWindow *>(window->handle());
-        if (!waylandWindow) {
-            qCWarning(LAYERSHELLQT) << window << "is not a wayland window. Not creating zwlr_layer_surface";
-            return false;
-        }
-
-        static QWaylandLayerShellIntegration *shellIntegration = nullptr;
-        if (!shellIntegration) {
-            shellIntegration = new QWaylandLayerShellIntegration();
-            if (!shellIntegration->initialize(waylandWindow->display())) {
-                delete shellIntegration;
-                shellIntegration = nullptr;
-                qCWarning(LAYERSHELLQT)
-                    << "Failed to initialize layer-shell integration, possibly because compositor does not support the layer-shell protocol";
-                return false;
-            }
-        }
-        waylandWindow->setShellIntegration(shellIntegration);
+        initializeShell();
     }
     return false;
 }
 
+void Window::initializeShell()
+{
+    auto waylandWindow = dynamic_cast<QtWaylandClient::QWaylandWindow *>(d->parentWindow->handle());
+    if (!waylandWindow) {
+        qCWarning(LAYERSHELLQT) << d->parentWindow << "is not a wayland window. Not creating zwlr_layer_surface";
+        return;
+    }
+
+    static QWaylandLayerShellIntegration *shellIntegration = nullptr;
+    if (!shellIntegration) {
+        shellIntegration = new QWaylandLayerShellIntegration();
+        if (!shellIntegration->initialize(waylandWindow->display())) {
+            delete shellIntegration;
+            shellIntegration = nullptr;
+            qCWarning(LAYERSHELLQT) << "Failed to initialize layer-shell integration, possibly because compositor does not support the layer-shell protocol";
+            return;
+        }
+    }
+    waylandWindow->setShellIntegration(shellIntegration);
+}
+
 Window *Window::get(QWindow *window)
 {
     if (!window) {
diff --git a/src/interfaces/window.h b/src/interfaces/window.h
index 9c084c7..b9e4824 100644
--- a/src/interfaces/window.h
+++ b/src/interfaces/window.h
@@ -150,6 +150,8 @@ Q_SIGNALS:
     void layerChanged();
 
 private:
+    void initializeShell();
+
     Window(QWindow *window);
     QScopedPointer<WindowPrivate> d;
 };