diff --git a/src/widgets/itemviews/qabstractitemview.cpp b/src/widgets/itemviews/qabstractitemview.cpp
index c3f8dd894e..f879af6ad2 100644
--- a/src/widgets/itemviews/qabstractitemview.cpp
+++ b/src/widgets/itemviews/qabstractitemview.cpp
@@ -3234,8 +3234,10 @@ void QAbstractItemView::setIndexWidget(const QModelIndex &index, QWidget *widget
         widget->installEventFilter(this);
         widget->show();
         dataChanged(index, index); // update the geometry
-        if (!d->delayedPendingLayout)
+        if (!d->delayedPendingLayout) {
             widget->setGeometry(visualRect(index));
+            d->doDelayedItemsLayout();  // relayout due to updated geometry
+        }
     }
 }
 
diff --git a/tests/auto/widgets/itemviews/qtreeview/tst_qtreeview.cpp b/tests/auto/widgets/itemviews/qtreeview/tst_qtreeview.cpp
index b2ca62227f..0580c466cf 100644
--- a/tests/auto/widgets/itemviews/qtreeview/tst_qtreeview.cpp
+++ b/tests/auto/widgets/itemviews/qtreeview/tst_qtreeview.cpp
@@ -952,6 +952,7 @@ void tst_QTreeView::indexWidget()
     QStandardItemModel treeModel;
     initStandardTreeModel(&treeModel);
     view.setModel(&treeModel);
+    view.resize(300, 400);  // make sure the width of the view is larger than the widgets below
 
     QModelIndex index = view.model()->index(0, 0);
 
@@ -980,6 +981,7 @@ void tst_QTreeView::indexWidget()
 
     //now let's try to do that later when the widget is already shown
     view.show();
+    QVERIFY(QTest::qWaitForWindowExposed(&view));
     index = view.model()->index(1, 0);
     QVERIFY(!view.indexWidget(index));