I don't recall anyone else reporting a similar problem...
If you start a new game, do the tooltips show up for both main characters? (would expect so, if older games work fine)
Please email supportdos@larian.com, with a description of the problem and the report.zip file generated by the
D:OS support tool. The zip file will contain your saves, which should hopefully help Larian figure out what the problem is.
You may have tried this already, but if you remove all your equipment and drag a potion/scroll into each of your skillbar slots, does that make a difference? What if you then re-equip your items and re-assign skills?
