Widgets work in jupyter notebook, but not in lab

[amirebrahimi]

The instructions say to open a web browser to http://localhost:8888/lab, but if you run any of the notebooks in lab the widgets either won't render or won't be interactive. I did notice that if I relaunch the notebook from lab, then the widgets will render correctly:

Is this a known issue? If not, then perhaps updating the documentation would be worthwhile to mention running the notebooks from notebook mode in lab rather than the default viewer.