TableModel supports complex row structures but only with a limited functionality. Since the model does not know how a complex row is structured, it cannot manipulate it. This also means that the copy of the model data that is stored in rows is not kept in sync with the source data that was set in QML - the user is supposed to handle simple data manipulation. This one functionality was not tested and it seems that the implementation was changed in the background as setRows is now called when rows is modified in QML. A good example is in complex.qml. If we try to extend the corresponding test case with a setData call it is going to call the function assigned to setDisplay which calls setRows - something it was not supposed to do. The checks in setRows do not recognize the complex row structure and as such the call is not successful. The checks could be adjusted to work for this specific case, but the structure could be anything so that solution would not be generic enough. Remove the support of manipulation of complex row structures from QQmlTableModel. [ChangeLog][Qt labs QML Models] Removed the support of manipulation of complex row structures from QQmlTableModel. Task-number: QTBUG-138553 Pick-to: 6.10 Change-Id: I8664ae9ec2e5cd09bc2c88a25f4ac972378e8e94 Reviewed-by: Mitch Curtis <mitch.curtis@qt.io>