throws NotImplementedException
      protected void insertAtBoundary(JEditorPane editor,                                      HTMLDocument doc, int offset,                                      Element insertElement,                                      String html, HTML.Tag parentTag,                                      HTML.Tag addTag)        throws NotImplementedException      {        /*        As its name implies, this protected method is used when HTML is inserted at a        boundary. (A boundary in this case is an offset in doc that exactly matches the        beginning offset of the parentTag.) It performs the extra work required to keep        the tag stack in shape and then calls insertHTML(). The editor and doc argu-        ments are the editor pane and document where the HTML should go. The offset        argument represents the cursor location or selection start in doc. The insert-        Element and parentTag arguments are used to calculate the proper number of        tag pops and pushes before inserting the HTML (via html and addTag, which are        passed directly to insertHTML()).        */        // FIXME: not implemented      }