Again: Widget Javascript not detected

I keep getting the infamous

“Widget Javascript not detected. It may not be installed or enabled properly.”

In the past, I have spent several hours trying to install all packages via the package manager or all packages via pip and enabling widgetsnbextensions on various levels, to no avail.

Since I have never seen Jupyter without that obnoxious error message although there is never any noticeable actual problem I would like to ask:

Has someone successfully blocked this message in some way? Like have the browser filter it out or compile Jupyter without it? Anything that avoids the seemingly impossible task to resolve it?

I have a nice little Jupyter notebook to present something to students but it’s useless as long as the screen keeps getting flooded with this error message.

Many thanks in advance for any suggestions!

What version of notebooks, widgetsnbextension, etc. are you using? Can you give instructions for setting up a fresh current environment where you get this message?