title: Richbox doesn't update while method is running
body: <p>Sorry for the inappropriate title. I have program as below </p>
  
  <pre><code>int status = 100;
  richTextBox1.AppendText("Starting Process....." + "\n");
  
  status = comm.WriteData(cmd1);
  if (status == 0)
  {
      richTextBox1.AppendText("COMMAND 1 OK" + "\n");
  }
  else
  {
      richTextBox1.AppendText("COMMAND 1 NOT OK" + "\n");
  }
  richTextBox1.AppendText("Gathering signal from product sensor....." + "\n");
  status = comm.WriteData(cmd2);
  if (status == 0)
  {
      richTextBox1.AppendText("COMMAND 2 OK" + "\n");
  }
  else
  {
      richTextBox1.AppendText("COMMAND 2 NOT OK" + "\n");
  }
  richTextBox1.AppendText("Measuring current value" + "\n");
  status = comm.WriteData(cmd3);
  if (status == 0)
  {
      richTextBox1.AppendText("COMMAND 3 OK" + "\n");
  }
  else
  {
      richTextBox1.AppendText("COMMAND 3 NOT OK" + "\n");
  }
  </code></pre>
  
  <p>This will execute on a button click event. Like this I need to send 130 commands. The overall process takes almost 6 minutes. The code works fine. But until the execution of all commands (for 6 minutes), the <code>RichTextBox</code> appears to be empty. After execution of each command I need to display message to operator whether the command is OK or NOT OK. I even tried by giving delay between each command. but can't achieve what I need. Please support to resolve this.  </p>