Method addTab

app/src/processing/app/Editor.java:1546–1553

Add a new tab. @param file The file to show in the tab. @param contents The contents to show in the tab, or null to load the contents from the given file. @throws IOException

(SketchFile file, String contents)

   * @throws IOException
   */
  protected void addTab(SketchFile file, String contents) throws IOException {
    EditorTab tab = new EditorTab(this, file, contents);
    tab.getTextArea().getDocument()
        .addDocumentListener(new DocumentTextChangeListener(
            () -> updateUndoRedoState()));
    tabs.add(tab);
    reorderTabs();
  }

  protected void removeTab(SketchFile file) throws IOException {
    int index = findTabIndex(file);