You can edit both the pre-defined and the custom widgets. The only exception being the URL value of the pre-defined widgets. 

To edit a widget: 

1. Rollover your mouse on a widget to highlight the edit option. 
2. Click Edit.
3. In the Edit Widget page, you can edit the Name, Description, URL(for custom widgets only) and display preferences for that widget. 

4. Select an option to show the widget to all users accessing the customer portal or only to those who have logged in.

5. Click Save.