choosing scrolling column seems not working at every website

[rhicore]

Some website may have multiple scrollable columns And it says I can select a mark which is at the top-left corner of a scrollable area after pressing f, But until now I haven't applied this characteristic successfully, for example I totally have no idea how to choose the left column of choosing different dialoge at chagpt.com. Maybe we should add a different and new way to choose page areas with like number 12345? It may conflict in text-type jump mode, but i think it's feasible in normal mode.