I see that `legacy` means `P2PKH` in both command line options and RPC help info:
```
-addresstype
What type of addresses to use ("legacy", "p2sh-segwit", or "bech32", default: "p2sh-segwit") 
```
```
getnewaddress ( "label" "address_type" )
...
2. address_type    (string, optional, default=set by -addresstype) The address type to use. Options are "legacy", "p2sh-segwit", and "bech32".
...
```

The useLegacyAddress checkbox describes itself as “Generate legacy address” - however, it actually makes the wallet GUI generate “p2sh-segwit” address for the user if it's checked.
{
    const RecentRequestsTableModel *submodel = model->getRecentRequestsTableModel();
    ReceiveRequestDialog *dialog = new ReceiveRequestDialog(this);
    dialog->setModel(model);
    dialog->setInfo(submodel->entry(index.row()).recipient);
    dialog->setAttribute(Qt::WA_DeleteOnClose);
    dialog->show();
}
void ReceiveCoinsDialog::recentRequestsView_selectionChanged(const QItemSelection &selected, const QItemSelection &deselected)
{
    
    bool enable = !ui->recentRequestsView->selectionModel()->selectedRows().isEmpty();
    ui->showRequestButton->setEnabled(enable);
    ui->removeRequestButton->setEnabled(enable);
}
void ReceiveCoinsDialog::on_showRequestButton_clicked()
{
    if(!model || !model->getRecentRequestsTableModel() || !ui->recentRequestsView->selectionModel())
        return;
    QModelIndexList selection = ui->recentRequestsView->selectionModel()->selectedRows();
    for (const QModelIndex& index : selection) {
        on_recentRequestsView_doubleClicked(index);
    }
}
void ReceiveCoinsDialog::on_removeRequestButton_clicked()