@Nullable
 @NonNls
 public Object getData(@NonNls String dataId) {
   if (LangDataKeys.PSI_ELEMENT.is(dataId)) {
     final PackageDependenciesNode selectedNode = myRightTree.getSelectedNode();
     if (selectedNode != null) {
       final PsiElement element = selectedNode.getPsiElement();
       return element != null && element.isValid() ? element : null;
     }
   }
   if (PlatformDataKeys.HELP_ID.is(dataId)) {
     return "dependency.viewer.tool.window";
   }
   return null;
 }