2 files changed, 12 insertions, 3 deletions
diff --git a/src/controls/Private/qquickcontrolsettings.cpp b/src/controls/Private/qquickcontrolsettings.cpp
index 95c656b2..d06f931a 100644
--- a/src/controls/Private/qquickcontrolsettings.cpp
+++ b/src/controls/Private/qquickcontrolsettings.cpp
@@ -161,7 +161,7 @@ QQmlComponent *QQuickControlSettings1::styleComponent(const QUrl &styleDirUrl, c
         styleFileUrl = makeStyleComponentUrl(controlStyleName, m_styleMap.value(QStringLiteral("Base")).m_styleDirPath);
     }
 
-    return new QQmlComponent(qmlEngine(control), styleFileUrl);
+    return new QQmlComponent(qmlEngine(control), styleFileUrl, this);
 }
 
 static QString relativeStyleImportPath(QQmlEngine *engine, const QString &styleName)
diff --git a/src/controls/Private/qquicktreemodeladaptor.cpp b/src/controls/Private/qquicktreemodeladaptor.cpp
index 495abc9c..287b388f 100644
--- a/src/controls/Private/qquicktreemodeladaptor.cpp
+++ b/src/controls/Private/qquicktreemodeladaptor.cpp
@@ -283,6 +283,8 @@ QItemSelection  QQuickTreeModelAdaptor1::selectionForRowRange(const QModelIndex
             return QItemSelection();
         return QItemSelection(toIndex, toIndex);
     }
+
+    to = qMax(to, 0);
     if (from > to)
         qSwap(from, to);
 
@@ -360,8 +362,15 @@ void QQuickTreeModelAdaptor1::showModelChildItems(const TreeItem &parentItem, in
     if (start == 0) {
         startIdx = rowIdx;
     } else {
-        const QModelIndex &prevSiblingIdx = m_model->index(start - 1, 0, parentIndex);
-        startIdx = lastChildIndex(prevSiblingIdx) + 1;
+        // Prefer to insert before next sibling instead of after last child of previous, as
+        // the latter is potentially buggy, see QTBUG-66062
+        const QModelIndex &nextSiblingIdx = m_model->index(end + 1, 0, parentIndex);
+        if (nextSiblingIdx.isValid()) {
+            startIdx = itemIndex(nextSiblingIdx);
+        } else {
+            const QModelIndex &prevSiblingIdx = m_model->index(start - 1, 0, parentIndex);
+            startIdx = lastChildIndex(prevSiblingIdx) + 1;
+        }
     }
 
     int rowDepth = rowIdx == 0 ? 0 : parentItem.depth + 1;