Function walk_path_mut 

pub fn walk_path_mut<'a>(
    root: &'a mut dyn Widget,
    path: &[usize],
) -> Option<&'a mut dyn Widget>

Walk the widget tree from root along path and return the deepest reachable widget as a mutable reference. Returns None if the path indexes past the available children at any level — useful when the path is stale (e.g. the tree shape changed since the inspector snapshot).