With a QTableView, setting SortingEnabled to true, followed by
setHorizontalHeader(...) leads to SortingEnabled to still be set to true, but it is not able to be sorted.

QTableView::setHorizontalHeader() connects various signals from the new header (sectionResized(), sectionMoved() etc.) to internal slots but does not connect QHeaderView::sortIndicatorChanged() to QTableView::sortByColumn() if sorting has been enabled on the table view earlier by calling setSortingEnabled(true). This has the effect of breaking sorting in the table.