Column information (passed to the render event).
render
The cell's <span class='wb-col'> element (null for plain trees).
<span class='wb-col'>
Column ID as defined in tree.columns definition ("*" for title column).
tree.columns
Column index (0: leftmost title column).
The value of tree.columns[] for the current index.
tree.columns[]
Column information (passed to the
render
event).