If you frequently use Data Snap you probably have noticed that the 'Export Description' field does not show historical values that you had entered previously. This result is due to an SAP setting that the user can control; here is what you can do:
1. From any SAPGUI session, select the Customize Local Layout icon, then Options
2. In the window that appears, open the Local Data folder and select History
3. Change the 'Enable History for Fields Up To' value from 59 to 60 (the 'Export Description' field is 60 characters in length)
4. Apply the changes; you should have to close your existing SAPGUI sessions and open new ones for this change to take affect
5. Once you return to Data Snap, you should be able to see history now for the 'Export Description' field as is visible in the capture below