code: public boolean isParamPanelOrChildSelected(String panelName) {
          DefaultMutableTreeNode node = getTreeNodeFromPanelName(panelName);
          if (node != null) {
              TreePath panelPath = new TreePath(node.getPath());
              if (getTreeParam().isPathSelected(panelPath)) {
                  return true;
              }
              TreePath selectedPath = getTreeParam().getSelectionPath();
              return selectedPath != null && panelPath.equals(selectedPath.getParentPath());
          }
          return false;
      }
docs: Tells whether or not the given param panel, or one of its child panels, is selected.
  
  @param panelName the name of the panel to check, should not be {@code null}.
  @return {@code true} if the panel or one of its child panels is selected, {@code false} otherwise.
  @since TODO add version
  @see #isParamPanelSelected(String)