Programmieren mit dBASE PLUS: hasButtons
Whether + and - icons are displayed for tree items that have children.
When hasButtons is true, tree items that have child items have a + or - icon to indicate whether the subtree is collapsed or expanded. Clicking the icon expands and collapses the tree.
Set hasButtons to false to prevent these icons from appearing. The user can still expand and collapse a subtree by pressing Shift+minus and Shift+plus on the numeric keypad. To prevent these keys from expanding or collapsing the tree, use the canExpand event.