File "electrum\gui\qt\main_window.py", line 571, in <lambda>
  File "electrum\gui\qt\main_window.py", line 279, in toggle_tab
  File "electrum\simple_config.py", line 149, in set_key
  File "electrum\simple_config.py", line 158, in _set_key_in_user_config
  File "electrum\simple_config.py", line 238, in save_user_config