Chrome Version: (71.0.3578.20 (Official Build) dev (64-bit)
OS: Mac

What steps will reproduce the problem?
(1) Open two Chrome windows and have bookmark bar showing with some content.
(2) Position windows such that one window is behind another with its bookmark bar behind the content area of the other window.
(3) Use command-` to switch to the window whose content area is above the bookmark bar. Put your cursor where the background window's bookmark bar is.
(4) Wait a few seconds.

What is the expected result?

The background window's bookmark bar tooltips do not show up.

What happens instead?

The background window's bookmark bar tooltips get shown even though your cursor is in a different window.