title: OutOfMemory exception in WinForms RichTextBox
body: <p>I'm using <code>RichTextBox</code> instances in few methods which are changing font, color, converting images to Rtf format.</p>
  
  <pre><code>public static string ColorText(string text)
  {
      System.Windows.Forms.RichTextBox rtb = new System.Windows.Forms.RichTextBox();
  
      rtb.Text = conversation;
  
      // find predefined keywords in text, select them and color them
  
      return rtb.Rtf;
  }
  </code></pre>
  
  <p>After a while I'm getting <code>OutOfMemory</code> Exception. Should I call <code>rtb.Dispose();</code>? Or <code>GC.Collect</code> or use <code>using</code> Or whats the right way?</p>