[ Version ( since = "4.2" ) ]
public void set_node_create_func (TreeManagerNodeFunc? func)
Sets the function to be called when a new node is being created by this.
If func is null then each created node will be a
TreeNode object.
Specifying a custom TreeManagerNodeFunc function for example allows one to use specialized sub-classed TreeNode objects.
| this |
a TreeManager tree manager object |
| func |
a TreeManagerNodeFunc function pointer, or null |