SharePoint 2010 Autocomplete Lookup field

SharePoint 2010 Autocomplete Lookup field allows type ahead functionality while looking up values from the lookup list. It uses REST for specifying filters.

The source code and wsp of the project is available here.

Deployment steps:
Adding Solution:
stsadm.exe -o addsolution -filename C:\NY.Autocomplete.LookupField.wsp

Deploy Solution:
stsadm.exe -o deploysolution -name NY.Autocomplete.LookupField.wsp -immediate -allowgacdeployment

Consider a list named Company with following fields:
Title: consisting of names of companies
Active: Yes/No
Create a custom list named Employee and add create a column of type Autocomplete Lookup Field in it as shown:

In the REST Filter specify the following filter: and Active eq true
This will make sure that only those companies show up which have Active set to Yes.
Following image shows the results while using the Autocomplete Lookup column

Issuses you may face while using Autocomplete: