It's not really hidden - the paintbar is painted under it... you could change the color of either text or the paintbar, and it would show better.
The problem with doing micro-customizations like that is that the options just multiply out of control and no one knows about them.
What you can also do is make an "empty" paintbar - one that never has colors. Then place it on the chart showing as band on bottom before the other paintbar. Adjust its width to match the height of the text. That will push the next paintbar higher.