File "/usr/lib/python3/dist-packages/kivy/core/window/window_sdl2.py", line 747, in mainloop
    self._mainloop()
  File "/usr/lib/python3/dist-packages/kivy/core/window/window_sdl2.py", line 479, in _mainloop
    EventLoop.idle()
  File "/usr/lib/python3/dist-packages/kivy/base.py", line 342, in idle
    self.dispatch_input()
  File "/usr/lib/python3/dist-packages/kivy/base.py", line 327, in dispatch_input
    post_dispatch_input(*pop(0))
  File "/usr/lib/python3/dist-packages/kivy/base.py", line 293, in post_dispatch_input
    wid.dispatch('on_touch_up', me)
  File "kivy/_event.pyx", line 707, in kivy._event.EventDispatcher.dispatch
  File "/usr/lib/python3/dist-packages/kivy/uix/behaviors/button.py", line 179, in on_touch_up
    self.dispatch('on_release')
  File "kivy/_event.pyx", line 703, in kivy._event.EventDispatcher.dispatch
  File "kivy/_event.pyx", line 1214, in kivy._event.EventObservers.dispatch
  File "kivy/_event.pyx", line 1098, in kivy._event.EventObservers._dispatch
  File "/usr/lib/python3/dist-packages/kivy/lang/builder.py", line 64, in custom_callback
    exec(__kvlang__.co_value, idmap)
  File "/home/user/wspace/electrum/electrum/gui/kivy/uix/ui_screens/server.kv", line 35, in <module>
    app.choose_server_dialog(root)
  File "/home/user/wspace/electrum/electrum/gui/kivy/main_window.py", line 146, in choose_server_dialog
    ChoiceDialog(_('Choose a server'), sorted(servers), popup.ids.host.text, cb2).open()
  File "kivy/properties.pyx", line 863, in kivy.properties.ObservableDict.__getattr__