z-index issue for top nav of Stack exchange

Question

In stack-exchange - When we click on next privilege section of our profile and scroll little bit, the tool-tip overlaps the top navigation for all the browsers as below.

It's not a major CSS issue but it may be affecting other sections with same tool-tip, too. This can be solved by increasing the z-index as below.

.top-bar { z-index: 9999; }