2 files changed, 46 insertions, 2 deletions
diff --git a/src/gui/graphicsview/qgraphicslinearlayout.cpp b/src/gui/graphicsview/qgraphicslinearlayout.cpp
index 1588364..7e8d19f 100644
--- a/src/gui/graphicsview/qgraphicslinearlayout.cpp
+++ b/src/gui/graphicsview/qgraphicslinearlayout.cpp
@@ -275,13 +275,17 @@ void QGraphicsLinearLayout::insertItem(int index, QGraphicsLayoutItem *item)
         qWarning("QGraphicsLinearLayout::insertItem: cannot insert itself");
         return;
     }
+    Q_ASSERT(item);
+
+    //the order of the following instructions is very important because
+    //invalidating the layout before adding the child item will make the layout happen
+    //before we try to paint the item
+    invalidate();
     d->addChildLayoutItem(item);
 
-    Q_ASSERT(item);
     d->fixIndex(&index);
     d->engine.insertRow(index, d->orientation);
     new QGridLayoutItem(&d->engine, item, d->gridRow(index), d->gridColumn(index), 1, 1, 0, index);
-    invalidate();
 }
 
 /*!
diff --git a/tests/auto/qgraphicswidget/tst_qgraphicswidget.cpp b/tests/auto/qgraphicswidget/tst_qgraphicswidget.cpp
index ddc4f73..7f24ddc 100644
--- a/tests/auto/qgraphicswidget/tst_qgraphicswidget.cpp
+++ b/tests/auto/qgraphicswidget/tst_qgraphicswidget.cpp
@@ -184,6 +184,7 @@ private slots:
     void task250119_shortcutContext();
     void QT_BUG_6544_tabFocusFirstUnsetWhenRemovingItems();
     void QT_BUG_12056_tabFocusFirstUnsetWhenRemovingItems();
+    void QT_BUG_13865_doublePaintWhenAddingASubItem();
 };
 
 
@@ -3321,6 +3322,45 @@ void tst_QGraphicsWidget::QT_BUG_12056_tabFocusFirstUnsetWhenRemovingItems()
     //This should not crash
 }
 
+
+struct GreenWidget : public QGraphicsWidget
+{
+    GreenWidget() : count(0)
+    {
+    }
+
+    void paint ( QPainter * painter, const QStyleOptionGraphicsItem * option, QWidget * )
+    {
+        count++;
+        painter->setPen(Qt::green);
+        painter->drawRect(option->rect.adjusted(0,0,-1,-1));
+    }
+
+    int count;
+};
+
+void tst_QGraphicsWidget::QT_BUG_13865_doublePaintWhenAddingASubItem()
+{
+    QGraphicsScene scene;
+    QGraphicsView view(&scene);
+    QGraphicsWidget *widget =  new QGraphicsWidget;
+    widget->resize(100, 100);
+    scene.addItem(widget);
+    QGraphicsLinearLayout *layout = new QGraphicsLinearLayout(widget);
+
+    view.show();
+    QTest::qWaitForWindowShown(&view);
+
+
+    GreenWidget *sub =  new GreenWidget;
+    layout->addItem(sub);
+
+    QTest::qWait(100);
+    QCOMPARE(sub->count, 1); //it should only be painted once
+
+}
+
+
 QTEST_MAIN(tst_QGraphicsWidget)
 #include "tst_qgraphicswidget.moc"