This is a long-known problem, but as it was encountered in a formal test, I'm reporting it again.
In step 19 of the Firefly.ipynb test notebook, the line
tbl_id = ffplt.upload_table(psf_src, title='Source Catalog')
results in the successful overlay of the table on an image, but the table itself ends up positioned off-screen ( ) in the "Slate" environment in the Firefly JupyterLab extension. It can be reached by scrolling ( ), but the results are unsatisfactory, as the resulting width of the image and table are also inappropriate.