Some issue with selectsql type of field

Hello
in a form i have created in the past (and was working like a charm), now i have the following problem...

I use a field of type selectsql.

This field gets some values fro the database and lists them to the user that fill the form to select.
The SQL statement used is...
SELECT DISTINCT a.username AS label, a.id, b.fromuser, b.touser AS value FROM #__users a left join #__jchat b on b.fromuser = a.id WHERE b.touser='${user:id}' ORDER BY label ASC;

and it gives no errors. Right now test says "success: found 4 entries"

At the front end i see correctly the 4 different values.

Now when i select one of the values of the selectsql field, i always get "Please select no more than 1 option(s) for field xxx" when submitting the form.

Can you please advise how to solve this problem?

Hello liaskas,

my advice for fixing the incorrectly filled form is to make sure the sql listbox has all option values unique.

I suspect that it is not due to the Visforms field configuration.
I also suspect that your SQL statement produces, at least in part, identical values in the options values.
So it's up to the data or the SQL statement.

Here is a small example.
The error occurs when you select the ''label-1-a' or ''label-1-a' options.
The error does not occur when you select the ''label-3' or ''label-4' options.

select 'label-1-a' as label, 'value-1' as value
union select 'label-1-b' as label, 'value-1' as value
union select 'label-3' as label, 'value-3' as value
union select 'label-4' as label, 'value-4' as value;

Kind regards, Ingmar