Programmieren mit dBASE PLUS: Events: onExpand
Event fired after a checkbox in a tree item is clicked.
The TreeItem whose + or - has been clicked.
The onExpand event fires after the user has expanded or collapsed a tree item’s subtree through the user interface, usually by clicking the + or - icon. Check the expanded property of the tree’s currently selected tree item to see whether the subtree is now expanded or not.