@NotNull
    @Override
    public Object[] getChildElements(@NotNull Object obj) {
      final Object[] childElements = super.getChildElements(obj);
      List l = new ArrayList(childElements.length);
      for (Object o : childElements) {
        if (o instanceof ProjectViewNode) {
          final ProjectViewNode node = (ProjectViewNode)o;
          final Object element = node.getValue();
          if (element instanceof PsiFile) {
            if (XsltSupport.isXsltFile((PsiFile)element)) {
              l.add(o);
            }
          }
          else {
            l.add(o);
          }
        }
      }
      return l.size() != childElements.length ? (Object[])l.toArray(new Object[l.size()]) : childElements;
    }
@NotNull
    @Override
    public Object[] getChildElements(@NotNull Object obj)