Why does the change display until I touch the screen?

Why does the change display until I touch the screen?

If the system has change to provide the customer after a transaction has been processed the system will display the change


The system can be configured to automatically reset after a period of X secs. 

How to configure: 
1. Go to Setup > Global Options > General & Locate the Reset Finalized Sale Time set this to the number of seconds desired. 
2. Exit & Save