void updateSceneRect(const QRectF &rect);
qreal _viewportHeight;
ColumnHandleItem *_firstColHandle, *_secondColHandle;
qreal _firstColHandlePos, _secondColHandlePos;
void updateSceneRect(const QRectF &rect);
qreal _viewportHeight;
ColumnHandleItem *_firstColHandle, *_secondColHandle;
qreal _firstColHandlePos, _secondColHandlePos;