Not a segfault, I get this:
Qt Code: 
  1. ASSERT failure in QList<T>::operator[]: "index out of range", file /usr/include/qt4/QtCore/qlist.h, line 403
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when I try to use sender[6] to get the row and/or column.

This looks to me that ther is no sixth column in the table, but there is. I can force it to get column six by hardcodeing in a 6,
Qt Code: 
  1. QCheckBox *mcb = qobject_cast<QCheckBox*>(m_ui->tableWidget->cellWidget(item->row(), 6));
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but I can't get column six using
Qt Code: 
  1. QCheckBox *mcb = qobject_cast<QCheckBox*>(m_ui->tableWidget->cellWidget(item->row(), selected[6]->column()));
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Why!?

Had to wrap the Assert in code or the second colon after QList<T> showed up as a smilie..