Problem displaying a column in a ProxyModel

[p91paul]

I've subclassed QSortFilterProxyModel and overridden the data() method to show two columns (name and surname) in a combobox as a single element.
the combobox is mapped in a QWidgetMapper to edit a database.
here's the problem: i select an element, then i click on another part of the window and my selection changes, and another element is selected automatically (it seems to be a random choice).

here is the data() function:
@
QVariant MyProxyModel::data(const QModelIndex & index,int role) const{
if (index.column()==1 && role==Qt::DisplayRole){
QModelIndex name = mapToSource(index);
QModelIndex surname = name.sibling(name.row(),name.column()+1);
return (sourceModel()->data(name).toString()+" "+
sourceModel()->data(surname).toString()).trimmed();
}
else return QSortFilterProxyModel::data(index,role);

}@

here is the mapping:
@
mapper->addMapping(ui->comboBox,column);
MyProxyModel *opm = new MyProxyModel(this);
opm->setSourceModel(model->relationModel(1));
ui->comboBox->setModel(opm);
ui->comboBox->setModelColumn(1);
model->relationModel(1)->select();@

another info: the issue exist only if i select an entry that effectively has a surname to concat; if i select someone with an empty surname my selection is conserved (obviously, the empty surname is a strange situation that exist because for testing I haven't inserted full names for everybody)

[p91paul]

discovered something: the problem is caused by the delegate.

@
mapper->setItemDelegate(new QSqlRelationalDelegate(mapper));@

when the real data is different from the proxy data, it makes crazy things.
however, i don't know how to handle this.

[p91paul]

well, exploring a bit, I've discovered the problem is inside qt. Since I have no time (and probably not enough skills) to remake the qsqlrelationalmodel class I'm stopping to use it and handle it by hand. when everything would be stable, I will post in the wiki my code snippets, and I hope it would be useful to somebody.
Paolo