title: Add an existing DataSet to Report .rdlc
body: <p>I have a Report.
  I need to create another one, similar to the one I have. So I created a second report by copying the first one.
  Then I created a new DataSet for the new report. I created it also by copying the original dataset (from the first report), and changing the name.
  Now, when I want to add the new DataSet in the new Report, it doesn't appear in DataSet option in "new Dataset.."</p>
  
  <p><img src="https://i.stack.imgur.com/RVmKA.png" alt="enter image description here"></p>
  
  <p>What am I missing? Why can't I see the DataSet that I've created?</p>