Для повторения проблемы нужно:
1. Запустить writer
2. Изменить размер окна так, чтобы появились горизонтальная и вертикальная линейки прокрутки
3. Напечатать текст ('123' - достаточно)
4. Выделить текст
5. Начать перетаскивание мышью
6. Навести курсор во время перетаскивания на линейку прокрутки

При запуске lowriter из консоли при этом выводится следующая диагностика:

$ lowriter
QPixmap: It is not safe to use pixmaps outside the GUI thread
QPixmap: It is not safe to use pixmaps outside the GUI thread
QPainter::begin: Paint device returned engine == 0, type: 2
QPainter::save: Painter not active
QPainter::setRenderHint: Painter must be active to set rendering hints
QPainter::setPen: Painter not active
QPainter::drawPath: Painter not active
QPainter::setRenderHint: Painter must be active to set rendering hints
QPainter::setRenderHint: Painter must be active to set rendering hints
QPainter::setBrush: Painter not active
QPainter::setPen: Painter not active
QPainter::drawPath: Painter not active
QPainter::setRenderHint: Painter must be active to set rendering hints
QPainter::restore: Unbalanced save/restore
QPainter::end: Painter not active, aborted
QPixmap: It is not safe to use pixmaps outside the GUI thread
QPixmap: It is not safe to use pixmaps outside the GUI thread
QPixmap: It is not safe to use pixmaps outside the GUI thread
QPixmap: It is not safe to use pixmaps outside the GUI thread
QPixmap: It is not safe to use pixmaps outside the GUI thread
QPixmap: It is not safe to use pixmaps outside the GUI thread
$ 

Аналогичная проблема по отношению к open office обсуждалась на форуме i-rs ( http://community.i-rs.ru/index.php/topic,15529.0.html )