@Override
  public Object getData(String dataId) {
    if (PlatformDataKeys.HELP_ID.is(dataId)) return HELP_ID;
    if (DATA_KEY.is(dataId)) return this;
    if (myTree == null) return null;
    TreePath[] paths = myTree.getSelectionPaths();

    if (paths == null || paths.length == 0) return null;

    if (paths.length > 1) {
      if (LangDataKeys.PSI_ELEMENT_ARRAY.is(dataId)) {
        return collectPsiElements();
      }
      return null;
    }

    TreePath path = paths[0];

    InspectionTreeNode selectedNode = (InspectionTreeNode) path.getLastPathComponent();

    if (selectedNode instanceof RefElementNode) {
      final RefElementNode refElementNode = (RefElementNode) selectedNode;
      RefEntity refElement = refElementNode.getElement();
      if (refElement == null) return null;
      final RefEntity item = refElement.getRefManager().getRefinedElement(refElement);

      if (!item.isValid()) return null;

      PsiElement psiElement = item instanceof RefElement ? ((RefElement) item).getElement() : null;
      if (psiElement == null) return null;

      final CommonProblemDescriptor problem = refElementNode.getProblem();
      if (problem != null) {
        if (problem instanceof ProblemDescriptor) {
          psiElement = ((ProblemDescriptor) problem).getPsiElement();
          if (psiElement == null) return null;
        } else {
          return null;
        }
      }

      if (CommonDataKeys.NAVIGATABLE.is(dataId)) {
        return getSelectedNavigatable(problem, psiElement);
      } else if (CommonDataKeys.PSI_ELEMENT.is(dataId)) {
        return psiElement.isValid() ? psiElement : null;
      }
    } else if (selectedNode instanceof ProblemDescriptionNode
        && CommonDataKeys.NAVIGATABLE.is(dataId)) {
      return getSelectedNavigatable(((ProblemDescriptionNode) selectedNode).getDescriptor());
    }

    return null;
  }