To use Qt with FlowLine2 You need to make the next modification: QTreeView::indexRowSizeHint must be Digital; the correspondig line in qtreeview.h should seem like: Web site legit???or ??is it|could it be|can it be} a fraud Web-site???or ??is this|Is that this} a safe website???or ??is this site serious?|Also fetching area values is much more hassl