Sets the column to draw the expander arrow at. It must be in @tree_view.
If @column is %NULL, then the expander arrow is always at the first
visible column.
If you do not want expander arrow to appear in your tree, set the
expander column to a hidden column.
Sets the column to draw the expander arrow at. It must be in @tree_view. If @column is %NULL, then the expander arrow is always at the first visible column.
If you do not want expander arrow to appear in your tree, set the expander column to a hidden column.