No module named 'webgui_jupyter_widgets'

Hi, it seems that some recent changes may have broken the NGSolve webgui. It worked in an Ubuntu build about three weeks ago, but with my build from today’s (April 24 commit bb6f627) source code, if I try to do:

from ngsolve.webgui import Draw

I get the error:

No module named ‘webgui_jupyter_widgets’

If I try to re-install the nbextension, I see this error:

jupyter nbextension install --user --py ngsolve
Installing /home/dow/ngsuite/ngsolve-install/lib/python3/dist-packages/ngsolve/nbextension/static → ngsolve_jupyter_widgets
Traceback (most recent call last):
File “/home/dow/.local/bin/jupyter-nbextension”, line 8, in
File “/home/dow/.local/lib/python3.8/site-packages/jupyter_core/”, line 270, in launch_instance
return super(JupyterApp, cls).launch_instance(argv=argv, **kwargs)
File “/home/dow/.local/lib/python3.8/site-packages/traitlets/config/”, line 664, in launch_instance
File “/home/dow/.local/lib/python3.8/site-packages/notebook/”, line 983, in start
super(NBExtensionApp, self).start()
File “/home/dow/.local/lib/python3.8/site-packages/jupyter_core/”, line 259, in start
File “/home/dow/.local/lib/python3.8/site-packages/notebook/”, line 711, in start
File “/home/dow/.local/lib/python3.8/site-packages/notebook/”, line 682, in install_extensions
full_dests = install(self.extra_args[0],
File “/home/dow/.local/lib/python3.8/site-packages/notebook/”, line 217, in install_nbextension_python
full_dest = install_nbextension(
File “/home/dow/.local/lib/python3.8/site-packages/notebook/”, line 194, in install_nbextension
_maybe_copy(src, full_dest, logger=logger)
File “/home/dow/.local/lib/python3.8/site-packages/notebook/”, line 1038, in _maybe_copy
if _should_copy(src, dest, logger=logger):
File “/home/dow/.local/lib/python3.8/site-packages/notebook/”, line 1014, in _should_copy
if os.stat(src).st_mtime - os.stat(dest).st_mtime > 1e-6:
FileNotFoundError: [Errno 2] No such file or directory: ‘/home/dow/ngsuite/ngsolve-install/lib/python3/dist-packages/ngsolve/nbextension/static’

The nbextension/static directory doesn’t seem to exist.


I have the same exact thing on my recent install on Linux Mint.

we recently moved the webgui to a seperate package, see installation instructions in the latest nightly-docu:

in short:

pip3 install webgui_jupyter_widgets
jupyter nbextension install --user --py webgui_jupyter_widgets
jupyter nbextension enable --user --py webgui_jupyter_widgets


Thanks, Joachim – that’s working fine for me.