Merge pull request #2927 from plotly/add-jupyter-detail

add some additional jupyter instructions

Author: nicolaskruchten

Diff for: doc/python/getting-started.md

@@ -174,7 +174,7 @@ fig = go.FigureWidget(data=go.Bar(y=[2, 3, 1]))
 fig
 ```
 
-Please check out our [Troubleshooting guide](/python/troubleshooting/) if you run into any problems with JupyterLab.
+Please check out our [Troubleshooting guide](/python/troubleshooting/) if you run into any problems with JupyterLab, particularly if you are using multiple python environments inside Jupyter.
 
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Diff for: doc/python/troubleshooting.md

@@ -77,7 +77,7 @@ To list your current extensions, run the following command in a terminal shell *
 $ jupyter labextension list
 ```
 
-Depending on your setup, it's possible for the command above to list the correct extensions but for them not to be loaded in the JupyterLab front-end you have loaded in your browser. To check if this is the problem, you can [look at the active extension list through your browser via the JupyterLab Extension Manager](https://jupyterlab.readthedocs.io/en/stable/user/extensions.html#using-the-extension-manager). This is important notably when you have per-kernel environments, or when you are using a centrally-hosted installation of JupyterLab. In such situations, `jupyter labextension list` may indicate that the extension is installed in a given environment, but it doesn't get loaded in your browser because JupyterLab is launched from a different environment.
+If you have [installed additional python environments](https://ipython.readthedocs.io/en/stable/install/kernel_install.html) (or kernels) to use with JupyterLab, or if you are using a centrally hosted JupyterLab installation, you need to make sure that the extensions are installed in the python environment used to launch JupyterLab (the "server" environment). If you accidentally installed the extensions (and run the command above) in one of the additional python environments ("processing" environments), then it is possible for the command above to list the correct extensions but for them to not be available in the JupyterLab front-end you have loaded in your browser. To check if this is the problem, you can [look at the active extension list through your browser via the JupyterLab Extension Manager](https://jupyterlab.readthedocs.io/en/stable/user/extensions.html#using-the-extension-manager), which will always list the extensions in the "server" environment. To summarize: if you use JupyterLab with multiple python environments, the extensions must be installed in the "server" environment, and the plotly python library must be installed in each "processing" environment that you intend to use. 
 
 If you have the correct version of the extensions installed and active in your active JupyterLab sessions and are still seeing problems, the issue may clear up if you rebuild JupyterLab. This shouldn't be required in principle but many users have resolved their issues this way. To rebuild JupyterLab, shut down JupyterLab and run the following command in a terminal shell **from the same environment as JupyterLab was launched**: