An often heard requirement is that users would expect the system to immediately navigate to the details screen of a found item if exactly one is found.
This is particularly expected if the user has searched for an item with a unique key field such as a business partner number. These users are right. What is the use of a search result screen if exactly one item is found? Why not go directly to the details of business partner, activity, opportunity, sales order etc?
SAP has agreed to this, and per beginning of 2011 they offered an OSS note to implement this. For more information, look at OSS Note 1548131 - CC1: Automatic navigation to search result (technical basis)
Beside the code correction instructions, this note also contains an attachment that explains the changes and how to make the changes have effect (you will also need to do some settings in business role customizing).
After implementing the note, you can add parameter 'ONE_HIT_DIRECT_DISPL' to the UI parameters profile, and set the value to 'true'. This will enable the one-hit functionality.