private boolean installTracker() {
    Document document = FileDocumentManager.getInstance().getDocument(myVirtualFile);
    if (document == null) return false;

    LineStatusTrackerManager.getInstance(myProject).requestTrackerFor(document, this);

    DocumentContent beforeContent = (DocumentContent)getContents().get(0);
    CharSequence beforeText = beforeContent.getDocument().getImmutableCharSequence();
    LineStatusTrackerManager.getInstanceImpl(myProject).offerTrackerContent(document, beforeText);
    return true;
  }
private boolean installTracker()