tidy up old code

backend/nodes/cursors.py

@@ -39,9 +39,6 @@ class Cursors:
         "On fields it reports x/y/z at both markers plus dx/dy/dz."
     )
 
-    _broadcast_overlay_fn = None
-    _current_node_id: str = ""
-
     def process(
         self, line, x1: float, y1: float, x2: float, y2: float,
         coord_pair=None,