addItem(_secondColHandle);
_secondColHandle->setXPos(_secondColHandlePos);
connect(_secondColHandle, SIGNAL(positionChanged(qreal)), this, SLOT(secondHandlePositionChanged(qreal)));
+
connect(this, SIGNAL(sceneRectChanged(const QRectF &)), _secondColHandle, SLOT(sceneRectChanged(const QRectF &)));
setHandleXLimits();