setHorizontalHeaderLabels question

QTableWidget::setHorizontalHeaderLabels(QStringLis t) method. When using it against the widget - horisontal headers (for columns) remain empty.

• I set up the # ofcolumns equal to the number of elements in the string list
• I see that HorizontalHeaderVisible property of the table in in QtDesigner is checked.
• I see values of the list for the header in the debugger allright
• I verified that nothing else sets up the header but this call
• I start entering items from the row 1. Row count is set prior to element insertion
• I am setting header labels as ui.tbl->setHorizontalHeaderLabels() prior to adding items

Question - what might be the problem?

Please provide a minimal compilable example reproducing the problem.