title: Charset in JTextPane which using AdvancedRTFEditorKit
body: <p>I'm having some problems with charset encodings. I'm using AdvancedRTFEditorKit (free closed source library: <a href="http://java-sl.com/advanced_rtf_editor_kit.html" rel="nofollow noreferrer">http://java-sl.com/advanced_rtf_editor_kit.html</a>). </p>
  
  <p>If I copy some special characters (ěščřžýáíé) from MS Word and paste them into sample delivered with AdvancedRtfEditorKit library, everything works fine. But if I do the same with my really simple SSCCE which uses AdvancedRTFEditorKit, then they appear as just rectangles. Do you know what I'm doing wrong?</p>
  
  <p><img src="https://i.stack.imgur.com/tA31Y.jpg" alt="enter image description here"></p>
  
  <p>This problem only occurs with MS Office products. LibreOffice works fine.</p>
  
  <p>My SSCCE:</p>
  
  <pre><code>public static void main(String[] args) {
      JFrame frame = new JFrame();
      frame.setSize(350, 300);
      frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
  
      JTextPane pane = new JTextPane();
      pane.setEditorKit(new AdvancedRTFEditorKit());
  
      frame.add(pane);
      frame.setVisible(true);
  }
  </code></pre>