I'm using generation of the BT from an XML document. Also using the blackboard to share some data between nodes. When BT nodes are created with buildTreeFromText, the blackboard is not yet available to nodes in their constructor (since it is not set yet on the node). Therefore, in the tick() override, I have to check if this is the first time tick() has been called so I can get/set data intializing data from the blackboard after construction. Perhaps the library itself should have an onInit() function, in addition to tick() and halt(). The derived classes could override this method and know that the blackboard is available.