+ _scene = new ChatScene(filter, filter->idString(), viewport()->width() - 2, this); // see below: resizeEvent()
+ connect(_scene, SIGNAL(sceneRectChanged(const QRectF &)), this, SLOT(sceneRectChanged(const QRectF &)));
+ connect(_scene, SIGNAL(lastLineChanged(QGraphicsItem *)), this, SLOT(lastLineChanged(QGraphicsItem *)));
+ setScene(_scene);
+
+ connect(verticalScrollBar(), SIGNAL(valueChanged(int)), this, SLOT(verticalScrollbarChanged(int)));