[Gambas-user] I want to clear a combobox

[francesco]

Why this code isn't working

  cmbSez.clear
  FOR EACH rData
    cmbSezioni.Add(rData["Sez"])

NEXT

It gives me "Index out of Range"

It seems that when I delete the content of a combobox, its index goes to -1.
I need to populate a combobox with a field resulting from a query, and every 
time I execute the query, the combobox should change with new records , but 
deleting previous values.

Francesco