title: DataGridView AllowUserToAddRow property doesn't work
body: <p>I have a simple project with Entity Framework, I have a <code>DataGridView</code> in my <code>Form</code> and I set its <code>AllowUserToAddRow</code> property to <code>true</code> but still I can not add new rows into it.</p>
  
  <p>And here is my code:</p>
  
  <pre><code>DBEntities context = new DBEntities();
  private void Form1_Load(object sender, EventArgs e)
  {
      var q = (from i in context.myTable
               select i).ToList();
      DataGridView.DataSource = q;
  }
  
  private void btnSave_Click(object sender, EventArgs e)
  {
      context.SaveChanges();
      MessageBox.Show("saved successfully");
  }
  </code></pre>
  
  <p>If I use a <code>BindingSource</code> control, it allow me to insert rows in <code>DataGridView</code> but with this approach after I call <code>context.SaveChanges()</code> nothing insert in my database file. So I thought maybe its relative to this problem that <code>DataGridView</code> with <code>true</code> <code>AllowUserToAddRow</code> property doesn't let me to insert row in <code>DataGridView</code>.</p>