The question is similar to pie chart. Basically, I have a bar chart, and the feature I wanted is that:
When mouse hover on bar, the according category axis label can be highlighted (customized color) too. Same goes that when mouse is over category axis label, the according bar area will be highlighted.
Same as selection behavior, I can click on category axis label to make a selection, drag-area to do multiple selection from category axis label, same as I do this from data plot area.