Save button does not work. File system provider for vscode-interactive:Figure%201.png is not available.

Each time I try to save a matplotlib plot generated by running a python script in an interactive window of Visual Studio Code 1.63.2 using %matplotlib ipympl , I get this error : "File system provider for vscode-interactive:Figure%201.png is not available."
The other buttons of the widget work fine.

3.8.12 (default, Oct 12 2021, 13:49:34)
[GCC 7.5.0]
ipympl version: 0.7.0
Selected Jupyter core packages...
IPython : 7.29.0
ipykernel : 6.4.1
ipywidgets : 7.6.5
jupyter_client : 6.1.12
jupyter_core : 4.9.1
jupyter_server : 1.4.1
jupyterlab : 3.2.1
nbclient : 0.5.3
nbconvert : 6.3.0
nbformat : 5.1.3
notebook : 6.4.6
qtconsole : 5.1.1
traitlets : 5.1.1
Known nbextensions:
config dir: /home/xavier/anaconda3/etc/jupyter/nbconfig
notebook section
jupyter-matplotlib/extension enabled
- Validating: OK
jupyter-js-widgets/extension enabled
- Validating: OK
JupyterLab v3.2.1
/home/xavier/anaconda3/share/jupyter/labextensions
jupyter-matplotlib v0.9.0 enabled OK
@jupyter-widgets/jupyterlab-manager v3.0.0 enabled OK (python, jupyterlab_widgets)

No source file or test is identified in the issue. Start by reproducing the save-button failure in VS Code 1.63.2 with a Python script using `%matplotlib ipympl`, then trace the interactive figure's save path; done means the button saves the plot without the unavailable file-system-provider error and has regression coverage.

Written by the indexing model from the issue text.