tight_layout KeyError default, matplotlib widget - matplotlib

Question

Using jupyterlab, i receive a KeyError: 'Default' when using plt.tight_layout() in combination with %matplotlib widget. The following code reproduces the issue:
import matplotlib.pyplot as plt
import numpy as np
%matplotlib widget
x=np.linspace(0,10)
y=x**2
plt.plot(x,y)
plt.tight_layout()
The complete error message is the following:
---------------------------------------------------------------------------
KeyError Traceback (most recent call last)
~/anaconda3/lib/python3.8/site-packages/matplotlib/backend_bases.py in _wait_cursor_for_draw_cm(self)
3024 try:
-> 3025 self.canvas.set_cursor(tools.Cursors.WAIT)
3026 yield
~/anaconda3/lib/python3.8/site-packages/matplotlib/backends/backend_webagg_core.py in set_cursor(self, cursor)
209 }, cursor=cursor)
--> 210 self.send_event('cursor', cursor=cursor)
211
~/anaconda3/lib/python3.8/site-packages/matplotlib/backends/backend_webagg_core.py in send_event(self, event_type, **kwargs)
391 if self.manager:
--> 392 self.manager._send_event(event_type, **kwargs)
393
~/anaconda3/lib/python3.8/site-packages/matplotlib/backends/backend_webagg_core.py in _send_event(self, event_type, **kwargs)
540 for s in self.web_sockets:
--> 541 s.send_json(payload)
542
~/anaconda3/lib/python3.8/site-packages/ipympl/backend_nbagg.py in send_json(self, content)
180 if content['type'] == 'cursor':
--> 181 self._cursor = cursors_str[content['cursor']]
182
KeyError: 'wait'
During handling of the above exception, another exception occurred:
KeyError Traceback (most recent call last)
/tmp/ipykernel_119035/3466922198.py in <module>
7 y=x**2
8 plt.plot(x,y)
----> 9 plt.tight_layout()
~/anaconda3/lib/python3.8/site-packages/matplotlib/pyplot.py in tight_layout(pad, h_pad, w_pad, rect)
2300 #_copy_docstring_and_deprecators(Figure.tight_layout)
2301 def tight_layout(*, pad=1.08, h_pad=None, w_pad=None, rect=None):
-> 2302 return gcf().tight_layout(pad=pad, h_pad=h_pad, w_pad=w_pad, rect=rect)
2303
2304
~/anaconda3/lib/python3.8/site-packages/matplotlib/figure.py in tight_layout(self, pad, h_pad, w_pad, rect)
3186 "compatible with tight_layout, so results "
3187 "might be incorrect.")
-> 3188 renderer = _get_renderer(self)
3189 with getattr(renderer, "_draw_disabled", nullcontext)():
3190 kwargs = get_tight_layout_figure(
~/anaconda3/lib/python3.8/site-packages/matplotlib/backend_bases.py in _get_renderer(figure, print_method)
1542 figure.canvas._get_output_canvas(None, fmt), f"print_{fmt}")
1543 try:
-> 1544 print_method(io.BytesIO())
1545 except Done as exc:
1546 renderer, = figure._cachedRenderer, = exc.args
~/anaconda3/lib/python3.8/site-packages/matplotlib/backend_bases.py in wrapper(*args, **kwargs)
1641 kwargs.pop(arg)
1642
-> 1643 return func(*args, **kwargs)
1644
1645 return wrapper
~/anaconda3/lib/python3.8/site-packages/matplotlib/_api/deprecation.py in wrapper(*inner_args, **inner_kwargs)
410 else deprecation_addendum,
411 **kwargs)
--> 412 return func(*inner_args, **inner_kwargs)
413
414 DECORATORS[wrapper] = decorator
~/anaconda3/lib/python3.8/site-packages/matplotlib/backends/backend_agg.py in print_png(self, filename_or_obj, metadata, pil_kwargs, *args)
538 *metadata*, including the default 'Software' key.
539 """
--> 540 FigureCanvasAgg.draw(self)
541 mpl.image.imsave(
542 filename_or_obj, self.buffer_rgba(), format="png", origin="upper",
~/anaconda3/lib/python3.8/site-packages/matplotlib/backends/backend_agg.py in draw(self)
431 self.renderer = self.get_renderer(cleared=True)
432 # Acquire a lock on the shared font cache.
--> 433 with RendererAgg.lock, \
434 (self.toolbar._wait_cursor_for_draw_cm() if self.toolbar
435 else nullcontext()):
~/anaconda3/lib/python3.8/contextlib.py in __enter__(self)
111 del self.args, self.kwds, self.func
112 try:
--> 113 return next(self.gen)
114 except StopIteration:
115 raise RuntimeError("generator didn't yield") from None
~/anaconda3/lib/python3.8/site-packages/matplotlib/backend_bases.py in _wait_cursor_for_draw_cm(self)
3026 yield
3027 finally:
-> 3028 self.canvas.set_cursor(self._lastCursor)
3029 else:
3030 yield
~/anaconda3/lib/python3.8/site-packages/matplotlib/backends/backend_webagg_core.py in set_cursor(self, cursor)
208 backend_tools.Cursors.RESIZE_VERTICAL: 'ns-resize',
209 }, cursor=cursor)
--> 210 self.send_event('cursor', cursor=cursor)
211
212 def set_image_mode(self, mode):
~/anaconda3/lib/python3.8/site-packages/matplotlib/backends/backend_webagg_core.py in send_event(self, event_type, **kwargs)
390 def send_event(self, event_type, **kwargs):
391 if self.manager:
--> 392 self.manager._send_event(event_type, **kwargs)
393
394
~/anaconda3/lib/python3.8/site-packages/matplotlib/backends/backend_webagg_core.py in _send_event(self, event_type, **kwargs)
539 payload = {'type': event_type, **kwargs}
540 for s in self.web_sockets:
--> 541 s.send_json(payload)
542
543
~/anaconda3/lib/python3.8/site-packages/ipympl/backend_nbagg.py in send_json(self, content)
179 # Change in the widget state?
180 if content['type'] == 'cursor':
--> 181 self._cursor = cursors_str[content['cursor']]
182
183 elif content['type'] == 'message':
KeyError: 'default'