ComboBox does not add items

[AstAn]

function setCurrencyList(lst : Array)
{
currentCurrencyCombobox.removeAll();
for(var i in lst)
{
currentCurrencyCombobox.addItem(lst[i].designation +' '+ lst[i].unit, i);
trace(lst[i].designation +' '+ lst[i].unit);
}
}

When I run this function the first time, everything works fine. When I run it a second time, all items are removed, but no new items are added.
Trace works fine, but the ComboBox does not.

Can anyone help me?

greetings
Daniel