title: Problem with datagridview: unexpected exception
body: <p>I have 1 MDI Parent form named as <code>MainForm</code> and 2 child forms WorkForm and <code>UserOp</code>.</p>
  
  <p><code>WorkForm</code> has <code>datagridview</code> that displays the <code>users</code> and its <code>datasource</code> is <code>BindingList</code>.the <code>BindingList</code> is created from a <code>List</code> of <code>type user</code> and list is declared in parent and is accessed in this with refrence i.e if i make any change to this list eventually it changes the list at parent. here is code how it is done.</p>
  
  <pre><code> MainForm mainForm;
   public WorkForm(MainForm main)
          {
  
              InitializeComponent();
              this.mainForm = main;
  }
  </code></pre>
  
  <p>similarly it is accessed from <code>UserOp</code>.now if i delete user from the list and WorkForm is already open then datagrid view gives default error that means i have to handle the <code>DataError</code> Event.I again update the <code>BindingList</code> and again assign it to <code>datagrid datasource</code>.</p>
  
  <p>this resolves the issue of error but after that exception is now shown sometimes not all times in <code>program.cs</code>
   this happens when after deleting I just take mouse over the form while it is inactive if form gets clicked then no exception.
  which reads<code>Specified argument was out of the range of valid values.
  Parameter name: e.RowIndex</code>
  at line  <code>Application.Run(new MainForm());</code></p>