In Eric4, when I select the "What's This" tool and then click on something to get a pop-up explanation, the resulting text appears white on yellow (unreadable). The tool-tips are fine (white on black). If I change the theme to any other, the text is black on yellow. I've found some posts on the internet about such behaviour with Skype and LibreOffice, but it doesn't seem to me to be the program-specific problem since it appears in various apps.
How can I tune it?