Figures in Output disappear if Output displayed twice in same cell

提供された Python ノートブック例で問題を再現し、Output ウィジェット内に matplotlib の図を作成した後、display(o) を 2 回呼び出します。リストされた JupyterLab、ipympl、matplotlib、ipywidgets のバージョンを使用して 1 回目と 2 回目の表示を比較します。繰り返し表示した後も図が表示されたままであれば完了です。

Describe the issue

Got an odd one.
If an Output contains a figure, and one calls a single cell containing display(Output) twice, the output "empties" and no figure is shown.

Example below. One can emphasise it by first calling display(o) in one cell, and then doing the double call (I press ctrl + Enter twice) in another cell. I attach a figure showing the result.

# in one cell:
%matplotlib widget
import matplotlib.pyplot as plt
from ipywidgets import Output
o = Output()
with o:
    plt.figure()
    plt.plot([1,2,3])
# In a separate cell, call this twice after each other
display(o)

Versions

 3.8.2 | packaged by conda-forge | (default, Mar 23 2020, 17:32:17) [MSC v.1916 64 bit (AMD64)]
ipympl version: 0.5.6
jupyter core     : 4.6.3
jupyter-notebook : 6.0.3
qtconsole        : 4.7.2
ipython          : 7.13.0
ipykernel        : 5.2.0
jupyter client   : 6.1.3
jupyter lab      : 2.1.4
nbconvert        : 5.6.1
ipywidgets       : 7.5.1
nbformat         : 5.0.4
traitlets        : 4.3.3
Known nbextensions:
  config dir: C:\Users\thomasaar\.jupyter\nbconfig
    notebook section
      default_cells disabled
  config dir: C:\Users\thomasaar\.conda\envs\py5\etc\jupyter\nbconfig
    notebook section
      ipyvolume/extension enabled
      - Validating: ok
      jupyter-webrtc/extension enabled
      - Validating: ok
      jupyter-matplotlib/extension enabled
      - Validating: ok
      plotlywidget/extension enabled
      - Validating: ok
      jupyter-js-widgets/extension enabled
      - Validating: ok
    tree section
      ipyparallel/main enabled
      - Validating: ok
JupyterLab v2.1.4
Known labextensions:
   app dir: C:\Users\thomasaar\.conda\envs\py5\share\jupyter\lab
        @jupyter-widgets/jupyterlab-manager v2.0.0 enabled  ok
        @jupyter-widgets/jupyterlab-sidecar v0.5.0 enabled  ok
        jupyter-matplotlib v0.7.2 enabled  ok```