{
if (event.equals(OpenFileEvent.class)
|| event.getClass().equals(OpenHistoryFileEvent.class)) {
setContent(new JPanel());
} else if (event.getClass().equals(ShowImageEvent.class)) {
ShowImageEvent ev = (ShowImageEvent) event;
imageViewerPanel.setImage(ev.getImage());
setContent(imageViewerPanel);
} else if (event.getClass().equals(ShowTextEvent.class)) {
ShowTextEvent ev = (ShowTextEvent) event;
textAreaViewerPanel.setText(ev.getContent());
setContent(textAreaViewerPanel);
}
}