When Sage overhauled the look and feel of ACT! 2010, they added a number of things to the navigation bar (the “navbar”) on the left side of the screen. One of the things they added was a Lookup box so you could do a search with less clicks.
This box allows you to quickly do a Lookup on the Contact field, or change the dropdown to choose another field instead.
However, not everyone searches the Contact field – maybe you use Last Name more often or you’ve added a custom field called “Customer ID” and use that all the time. Luckily, Exponenciel has provided a free ACT! addOn that will allow you to change it.