Barks at Strangers

A little setback in our progress...seems that Angela has become comfortable enough and protective of us (her pack) that she barks at strangers. Not just people that come to our home, but (much more worrisome) those that we pass on the street. A neighbor was gardening yesterday and Angela wouldn't stop barking as we walked by her house. People we pass while walking are likely to get some barking and jumping. We're working on having her sit while a stranger walks by, feeding her treats for cooperation and to associate strangers with possibly getting treats, but no progress so far. Any thoughts or ideas, you nice people who have adopted rescue dogs or dogs with "issues"? Thanks!