code: private boolean shouldInsertIntoSiblingList(int originalPathLevel, CmsTreeItem parent, int index) {
  
          if ((index <= 0) || (parent == null)) {
              return false;
          }
          return originalPathLevel != getPathLevel(parent.getPath());
      }
docs: Determines if the draggable should be inserted into the previous siblings children list.<p>
  
  @param originalPathLevel the original path level
  @param parent the parent item
  @param index the current index
  
  @return <code>true</code> if the item should be inserted into the previous siblings children list