Traceback (most recent call last):
  File "/usr/lib/python3/dist-packages/psutil/__init__.py", line 1044, in _send_signal
    os.kill(self.pid, sig)
PermissionError: [Errno 1] Operation not permitted

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/usr/bin/mate-tweak", line 639, in toggle_panel_features
    self.replace_panel_layout(self.base_layout)
  File "/usr/bin/mate-tweak", line 560, in replace_panel_layout
    self.kill_process('mate-panel')
  File "/usr/bin/mate-tweak", line 212, in kill_process
    process.kill()
  File "/usr/lib/python3/dist-packages/psutil/__init__.py", line 311, in wrapper
    return fun(self, *args, **kwargs)
  File "/usr/lib/python3/dist-packages/psutil/__init__.py", line 1118, in kill
    self._send_signal(signal.SIGKILL)
  File "/usr/lib/python3/dist-packages/psutil/__init__.py", line 1055, in _send_signal
    raise AccessDenied(self.pid, self._name)
psutil.AccessDenied: psutil.AccessDenied (pid=26964, name='mate-panel')