Zoho Mail: Contacts: Nick Name - not useable in "Compose"

In "compose" an email I would like to insert an email based on "Nick Name" in a Contact's record.

When I type the email address of that person, that email is inserted, or if there are multiple selections I am given a drop-down list to choose from (nice!); however, if I type the Nick Name of that contact, it does not insert the email or give me an option. What am I doing wrong? 

If the Nick Name is not able to be used in this way, then what is the purpose of the field?  This was something available in gMail...

Thanks,

Todd