Strange Keyword Error, where spaces exist

In all my keywords which are retrieved froma view lookup I get a strange error.

For example if the options are:

London

Paris

New York

If the user selects New York, the next time they go into the keyword list the options are:

London

Paris

New York

New

York

with York highlighted.

This happens on all my keywords. Anyone got any ideas what is causing this?

Subject: Strange Keyword Error, where spaces exist

Check the Multi vlaue separator options on the field properties and de-select ‘space’ as a multivalue separator.