I don't know of a way to do this with SAS/Graph dev=png and ods html output (only the mouse-over popup text, and the drilldown links).
Perhaps someone could add something clever with javascript to change the color of the hovered-over area(?)
2025 SAS Hackathon: There is still time!
Good news: We've extended SAS Hackathon registration until Sept. 12, so you still have time to be part of our biggest event yet – our five-year anniversary!