The column button is displayed if both the column header panel and indicator panel are visible. The column button has no default functionality. You can however, handle the TreeListState.ColumnButtonPressed event to perform specific actions each time an end-user clicks the button.
The table below lists the main properties which affect the element's appearance:
The TreeListAppearanceCollection.HeaderPanel property.
Note: the appearance settings which specify the background and border colors are ignored if a Tree List is painted in WindowsXP or Office2003 style.
Custom Draw Event
The TreeList.CustomDrawColumnHeader event.
The TreeList.IndicatorWidth property.
The TreeList.ColumnButtonClick event.