Method: WD_CREATE_CONTEXT
Method: WD_DESTROY_CONTEXT
Method: SET_MODELS
Method: CREATE_PURCHASEORDER
Method: CREATE_CONTEXT_NODES
Method: DO_PREPARE_OUTPUT
Method: UPDATE_SELECTED_ROWS
Method: EH_ONSELECT
Method: DO_INIT_CONTEXT
Method: DO_HANDLE_DATA
Method: UPDATE_SELECTION_MODE