title: SetParent not Working InvalidOperationException
body: <p>I recently tried to work on an old project I had an i am not able to get the setparent to work it keeps giving me the "InvalidOperationException" error, here is the code:</p>
  
  <pre><code>private void button1_Click(object sender, EventArgs e)
      {
          Process proc = Process.Start("calc.exe");
          proc.WaitForInputIdle();
          Thread.Sleep(500);
          SetParent(proc.MainWindowHandle, this.Handle);
      }
  </code></pre>
  
  <p>Its being called with a button and when it tries to set the parent it errors out. Everything i can find online say that my code is right.</p>