1 files changed, 28 insertions, 1 deletions
diff --git a/src/imports/layouts/qquicklayout.cpp b/src/imports/layouts/qquicklayout.cpp
index 3786d21727..55ee3b63c6 100644
--- a/src/imports/layouts/qquicklayout.cpp
+++ b/src/imports/layouts/qquicklayout.cpp
@@ -42,6 +42,7 @@
 #include <QtCore/qcoreapplication.h>
 #include <QtCore/private/qnumeric_p.h>
 #include <QtCore/qmath.h>
+#include <QtQml/qqmlinfo.h>
 #include <limits>
 
 /*!
@@ -678,7 +679,7 @@ QQuickLayout *QQuickLayoutAttached::parentLayout() const
         parentItem = parentItem->parentItem();
         return qobject_cast<QQuickLayout *>(parentItem);
     } else {
-        qWarning("Layout must be attached to Item elements");
+        qmlWarning(parent()) << "Layout must be attached to Item elements";
     }
     return 0;
 }
@@ -762,9 +763,11 @@ bool QQuickLayout::shouldIgnoreItem(QQuickItem *child, QQuickLayoutAttached *&in
 void QQuickLayout::itemChange(ItemChange change, const ItemChangeData &value)
 {
     if (change == ItemChildAddedChange) {
+        Q_D(QQuickLayout);
         QQuickItem *item = value.item;
         qmlobject_connect(item, QQuickItem, SIGNAL(baselineOffsetChanged(qreal)), this, QQuickLayout, SLOT(invalidateSenderItem()));
         QQuickItemPrivate::get(item)->addItemChangeListener(this, QQuickItemPrivate::SiblingOrder | QQuickItemPrivate::ImplicitWidth | QQuickItemPrivate::ImplicitHeight | QQuickItemPrivate::Destroyed | QQuickItemPrivate::Visibility);
+        d->m_hasItemChangeListeners = true;
         if (isReady())
             updateLayoutItems();
     } else if (change == ItemChildRemovedChange) {
@@ -802,6 +805,30 @@ bool QQuickLayout::isReady() const
     return d_func()->m_isReady;
 }
 
+/*!
+ * \brief QQuickLayout::deactivateRecur
+ * \internal
+ *
+ * Call this from the dtor of the top-level layout.
+ * Otherwise, it will trigger lots of unneeded item change listeners (itemVisibleChanged()) for all its descendants
+ * that will have its impact thrown away.
+ */
+void QQuickLayout::deactivateRecur()
+{
+    if (d_func()->m_hasItemChangeListeners) {
+        for (int i = 0; i < itemCount(); ++i) {
+            QQuickItem *item = itemAt(i);
+            // When deleting a layout with children, there is no reason for the children to inform the layout that their
+            // e.g. visibility got changed. The layout already knows that all its children will eventually become invisible, so
+            // we therefore remove its change listener.
+            QQuickItemPrivate::get(item)->removeItemChangeListener(this, QQuickItemPrivate::SiblingOrder | QQuickItemPrivate::ImplicitWidth | QQuickItemPrivate::ImplicitHeight | QQuickItemPrivate::Destroyed | QQuickItemPrivate::Visibility);
+            if (QQuickLayout *layout = qobject_cast<QQuickLayout*>(item))
+                layout->deactivateRecur();
+        }
+        d_func()->m_hasItemChangeListeners = false;
+    }
+}
+
 void QQuickLayout::itemSiblingOrderChanged(QQuickItem *item)
 {
     Q_UNUSED(item);