altair charts with tooltips in reveal.js presentations

[franz-haas-nx]

I have a very good experience with my altair charts when I

chart.save("out.html")

However, when they get into an reveal.js presentation by means of nbconvert, I get a bad expereince with the tooltips using the same chart.

I am using the html renderer. I did look at the html code, and the way vega is used and loaded is different in the two cases, however I am as of yet unable to identify where the issue comes from exactly.

any ideas?

thanks in advance
Franz