Expand buttons enable end-users to expand or collapse parent nodes (nodes that have children). When a parent node is collapsed, the node's expand button displays a 'plus' sign indicating that the node can be expanded by clicking the button. Once a node has been expanded, the node's button displays a 'minus' sign.
The table below lists the main properties that affect the element's appearance:
The TreeListOptionsView.ShowButtons option.
The TreeListAppearanceCollection.GroupButton property.
Note: the appearance settings are ignored if a Tree List is painted in WindowsXP or Office2003 style.
Custom Draw Event
The TreeList.CustomDrawNodeButton event.
The TreeListOptionsView.ExpandButtonCentered property.