DWA deafult mail client preference not being saved

I chose to make DWA my default mail client by clicking the ‘Make Default’ button under the Preferences>Basic screen. I can tell it is not selected because the Make Default button is ‘active’. Then clicked the OK button. The Saving Preferences screen graphic displays and the Make Default button is now “grayed out”. I go back into the preferences item and the Make Default button is now ‘active’ again. In otherwords, DWA is not the default mail client. Is there something I’m missing or is it a bug in the software?