IDLE crashes when "Configure IDLE" is selected through "Options". Terminal output is as follows:

[Stephen Gregory]

using xubuntu 16.04 LTS

IDLE3 crashes when "Configure IDLE" is selected through "Options". Terminal output is as follows:

Exception in Tkinter callback
Traceback (most recent call last):
  File "/usr/lib/python3.5/tkinter/__init__.py", line 1553, in __call__
    return self.func(*args)
  File "/usr/lib/python3.5/idlelib/EditorWindow.py", line 516, in config_dialog
    configDialog.ConfigDialog(self.top,'Settings')
  File "/usr/lib/python3.5/idlelib/configDialog.py", line 74, in __init__
    self.LoadConfigs()
  File "/usr/lib/python3.5/idlelib/configDialog.py", line 1086, in LoadConfigs
    self.LoadFontCfg()
  File "/usr/lib/python3.5/idlelib/configDialog.py", line 988, in LoadFontCfg
    self.SetFontSample()
  File "/usr/lib/python3.5/idlelib/configDialog.py", line 866, in SetFontSample
    self.labelFontSample.config(font=newFont)
  File "/usr/lib/python3.5/tkinter/__init__.py", line 1333, in configure
    return self._configure('configure', cnf, kw)
  File "/usr/lib/python3.5/tkinter/__init__.py", line 1324, in _configure
    self.tk.call(_flatten((self._w, cmd)) + self._options(cnf))
_tkinter.TclError: expected integer but got ""