Traceback (most recent call last):


 "/Users/dstansby/github/matplotlib/lib/matplotlib/cbook/__init__.py", line 216, in process

func(*args, **kwargs)


 "/Users/dstansby/github/matplotlib/lib/matplotlib/backend_bases.py", line 2830, in press_zoom

if (x is not None and y is not None and a.in_axes(event) and


 "/Users/dstansby/github/matplotlib/lib/matplotlib/axes/_base.py", line 2126, in in_axes

return self.patch.contains(mouseevent)[0]


 "/Users/dstansby/github/matplotlib/lib/matplotlib/patches.py", line 144, in contains

Path, np.split(vertices, idxs), np.split(codes, idxs))), {}


 "/Users/dstansby/miniconda3/lib/python3.7/site-packages/numpy/lib/shape_base.py", line 850, in split

res = array_split(ary, indices_or_sections, axis)


 "/Users/dstansby/miniconda3/lib/python3.7/site-packages/numpy/lib/shape_base.py", line 745, in array_split

Ntotal = len(ary)
TypeError: object of type 'NoneType' has no len()

Traceback (most recent call last):


 "site-packages\matplotlib\backends\backend_wx.py", line 1079, in _onLeftButtonDown


 "site-packages\matplotlib\backend_bases.py", line 1917, in button_press_event


 "site-packages\matplotlib\cbook.py", line 554, in process


 "site-packages\matplotlib\cbook.py", line 416, in __call__


 "CellProfiler\cellprofiler\gui\editobjectsdlg.py", line 871, in on_click


 "CellProfiler\cellprofiler\gui\editobjectsdlg.py", line 1654, in on_split_second_click


 "CellProfiler\cellprofiler\gui\editobjectsdlg.py", line 1453, in exit_split_mode


 "CellProfiler\cellprofiler\gui\editobjectsdlg.py", line 1197, in update_artists


 "site-packages\matplotlib\backends\backend_agg.py", line 451, in restore_region


 "site-packages\matplotlib\backends\backend_agg.py", line 359, in restore_region
TypeError: restore_region() argument 1 must be matplotlib.backends._backend_agg.BufferRegion, not None
