3476746 - Email Address is not Returning any Result in To field Search

When typing an email address in the To field of the email editor, there is no Contact, Employee or Customer shown in the search result.

Service Cloud Version 2

1. Go to Cases.
2. Open a Case.
3. Select Email Option.
4. Select the To field.
5. Start typing an Account Email Address.
6. No suggestion is given in Contact/Customer search.

The email address is not maintained as a contact, instead it is listed as email address on an account. This will not be found in To field search. 

In order for the address to be found it must be assigned to a contact within the account.

Email, Contact, Account, To , KBA , CEC-CRM-EML , Emails for SAP Sales/Service Cloud , Problem