title: RDLC Report Data doesn't update to reflect changes
body: <p>On my RDLC page, the "Report Data" window shows a custom dataset that it pulls fields from to display.  I've modified this DataSet with some additional tables.  However, these tables aren't shown and therefore I'm unable to select them for use in expressions (in the Expression window, under Datasets, there are only the tables that were originally there, not the additional tables I've added).  </p>
  
  <p>Refreshing the data source doesn't do anything, and if I right-click on it and select "New Dataset", I'm unable to select the parent data source (it doesn't appear in the drop down list).  What I mean is, if the data source is called "MyDataSet", and under that are other DataSets, if I right-click and go to "Add Dataset", it brings up the dialog box but "MyDataSet" is <strong>not</strong> in the list of available Data sources, even though I'm specifically saying I want to add a datatable to that data source.  The other, existing, datatables list it under the data source, but new ones do not.</p>
  
  <p>How do I refresh the data source so I can access these new tables in my report?</p>