Vertical scrollbar not exported to HTML

[aoeftiger]

I have enabled the vertical scrollbar via metadata 'scroll': 'true' (cf. RISE doc) and it works fine in live presentation mode.

Upon exporting to HTML, however, the scrollbar setting gets lost and vertically extending slide contents will simply be cut and become unaccessible.

I'm running nbconvert==7.2.5, notebook==6.5.2 and rise==5.7.1 .. (I have seen this effect in both chromium 105.0.5195.102 and firefox 104.0)

[aoeftiger]

minimal working example: https://github.com/aoeftiger/mwe-vertical-scrollbar-rise/tree/main

[aoeftiger]

remark: horizontal scrollbars seem to persist in both live presentation mode and HTML slides...

[aoeftiger]

I noted that the HTML MWE was not easy to see, here's a github.io version:
https://aoeftiger.github.io/mwe-vertical-scrollbar-rise

--> one can clearly see that the vertical scrollbar is not present on the HTML version of the slides, while the overflow on the lower part of the output is cut from view (in a typical viewport with 4:3 or similar ratio).