An Expand Button is displayed if the corresponding node has children, and enables end-users to expand or collapse it.
When a node is collapsed, the expand button displays a 'plus' sign, indicating that the node can be expanded by clicking the button. Once a node has been expanded, the button displays a 'minus' sign.
You can toggle the visibility of expand buttons via the ASPxTreeView.ShowExpandButtons property. Regardless of the property value, end-users can expand or collapse nodes by double-clicking them.
The table below lists the main properties which affect the element's appearance:
Member Table: Expanding and Collapsing Nodes