SharePoint Designer: Datasource List/Library window greyed out.

 A user has Full control of the site but when opening the site in SPD the datasource window is greyed out.  The access right to granted individually. It seems adding the user to Owners group takes care of the problem. So somehow somewhere the permission is not propagating correctly.

Steps to check and verify:
 

1.       Open the problem site in SPD

2.       In the Folder List navigate to _catalogs/fpdatasources

3.       Right-click fpdatasources and click the Security tab

4.       Click "Manage permissions using the browser."

5.       Add the appropriate permissions.