Thanks Norm.
I don't know if it's not allowed (it's working on all Oracle products we have). I will remove the tabs from my tnsnames.ora
But what I was describing also is that the connection to the database is working fine if I remove the squares from the selected list.
The behavior of the select list is different from the tnsname search.
Select List : keep Tabs (shown as squares) and passes them to the "tnsname search"
The "Tnsname search" seems to search removing Tabs, so does not find the select list parameter.