Traceback (most recent call last):
  File "electrum/gui/qt/qrreader/__init__.py", line 150, in _on_qr_reader_finished
  File "electrum/gui/qt/main_window.py", line 2143, in cb
  File "electrum/gui/qt/main_window.py", line 1109, in show_transaction
  File "electrum/gui/qt/transaction_dialog.py", line 420, in show_transaction
  File "electrum/gui/qt/transaction_dialog.py", line 565, in __init__
  File "electrum/gui/qt/transaction_dialog.py", line 909, in update
TypeError: bad operand type for abs(): 'NoneType'