Requires "Allow users to enter their own values" be enabled.

[spellacl]

Use of the extension requires "Allow users to enter their own values" be enabled for the field when field type is "Picklist (string)". Otherwise, input example such as "Windows; Linux; etc" is interpreted as a user-defined input, not an option from the picklist(String).

[mmanela]

You should use this extension with a multi-line text field and not a pick list field