Traceback (most recent call last):
  File "electrum\gui\qt\history_list.py", line 788, in <lambda>
  File "electrum\gui\qt\main_window.py", line 2924, in bump_fee_dialog
  File "electrum\gui\qt\rbf_dialog.py", line 146, in __init__
  File "electrum\gui\qt\rbf_dialog.py", line 38, in __init__
TypeError: unsupported operand type(s) for /: 'NoneType' and 'int'