public void addPageIntoEnd(Page page, Project project) {
    pagesInDocument.add(page);

    symbolOffsetToEndOfPage.add(
      (symbolOffsetToEndOfPage.isEmpty() ? 0 : symbolOffsetToEndOfPage.get(symbolOffsetToEndOfPage.size() - 1))
      + page.getText().length());

    runAsWriteAction(
      project,
      myDocument.getTextLength() == 0 ? () -> myDocument.setText(page.getText())
                                      : () -> myDocument.insertString(myDocument.getTextLength(), page.getText()));
  }
public void addPageIntoEnd(Page page, Project project)