%matplotlib widget run time error

Hello,
I saw an old issue about this topic, but I could not find a recent solution.
I am using a Linux machine, Python version 3.12.4. I created my environment and I installed matplotlib by using
`pip install matplotlib`

But when I run my code in VS code, I get a runtime error related to %matplotlib widget

> RuntimeError Traceback (most recent call last)
> File ~/.conda/envs/s_i/lib/python3.12/site-packages/matplotlib/backends/registry.py:413, in BackendRegistry.resolve_gui_or_backend(self, gui_or_backend)
> [412](https://file+.vscode-resource.vscode-cdn.net/home/Paola/Documents/~/.conda/envs/s_i/lib/python3.12/site-packages/matplotlib/backends/registry.py:412) try:
> --> [413](https://file+.vscode-resource.vscode-cdn.net/home/Paola/Documents/~/.conda/envs/s_i/lib/python3.12/site-packages/matplotlib/backends/registry.py:413) return self.resolve_backend(gui_or_backend)
> [414](https://file+.vscode-resource.vscode-cdn.net/home/Paola/Documents/~/.conda/envs/s_i/lib/python3.12/site-packages/matplotlib/backends/registry.py:414) except Exception: # KeyError ?
>
> File ~/.conda/envs/s_i/lib/python3.12/site-packages/matplotlib/backends/registry.py:375, in BackendRegistry.resolve_backend(self, backend)
> [374](https://file+.vscode-resource.vscode-cdn.net/home/Paola/Documents/~/.conda/envs/s_i/lib/python3.12/site-packages/matplotlib/backends/registry.py:374) if gui is None:
> --> [375](https://file+.vscode-resource.vscode-cdn.net/home/Paola/Documents/~/.conda/envs/s_i/lib/python3.12/site-packages/matplotlib/backends/registry.py:375) raise RuntimeError(f"'{backend}' is not a recognised backend name")
> [377](https://file+.vscode-resource.vscode-cdn.net/home/Paola/Documents/~/.conda/envs/s_i/lib/python3.12/site-packages/matplotlib/backends/registry.py:377) return backend, gui if gui != "headless" else None
>
> RuntimeError: 'widget' is not a recognised backend name
>
> During handling of the above exception, another exception occurred:
>
> RuntimeError Traceback (most recent call last)
> Cell In[3], [line 8](vscode-notebook-cell:?execution_count=3&line=8)
> [3](vscode-notebook-cell:?execution_count=3&line=3) from pathlib import Path
> [5](vscode-notebook-cell:?execution_count=3&line=5) #import ephyviewer
> [6](vscode-notebook-cell:?execution_count=3&line=6) #import spikeinterface_gui as sigui
> ----> [8](vscode-notebook-cell:?execution_count=3&line=8) get_ipython().run_line_magic('matplotlib', 'widget')
> [9](vscode-notebook-cell:?execution_count=3&line=9) get_ipython().run_line_magic('matplotlib', 'inline')
> [10](vscode-notebook-cell:?execution_count=3&line=10) #%matplotlib notebook
> ...
> [414](https://file+.vscode-resource.vscode-cdn.net/home/Paola/Documents/~/.conda/envs/s_i/lib/python3.12/site-packages/matplotlib/backends/registry.py:414) except Exception: # KeyError ?
> --> [415](https://file+.vscode-resource.vscode-cdn.net/home/Paola/Documents/~/.conda/envs/s_i/lib/python3.12/site-packages/matplotlib/backends/registry.py:415) raise RuntimeError(
> [416](https://file+.vscode-resource.vscode-cdn.net/home/Paola/Documents/~/.conda/envs/s_i/lib/python3.12/site-packages/matplotlib/backends/registry.py:416) f"'{gui_or_backend} is not a recognised GUI loop or backend name")
>
> RuntimeError: 'widget is not a recognised GUI loop or backend name

Have you found a solution for this issue?
thank you

Start by reproducing `%matplotlib widget` in the reported Linux, Python 3.12.4, and VS Code environment, then inspect the backend resolution path shown in `matplotlib/backends/registry.py`. Compare the behavior with the ipympl and Jupyter integration setup; done means the cause and a reproducible resolution are identified for this configuration.

Written by the indexing model from the issue text.