Scrolling job dropdown in merge request is laggy

Summary

Scrolling the job dropdown in a merge request is super laggy when there is a lot of jobs in it.

Steps to reproduce

1. Open any GitLab merge request
2. Open a pipeline stage dropdown
3. Scroll and notice lag

Example Project

(If possible, please create an example project here on GitLab.com that exhibits the problematic behavior, and link to it here in the bug report)

(If you are using an older version of GitLab, this will also determine whether the bug is fixed in a more recent version)

What is the current bug behavior?

Frame rate drops pretty badly.

What is the expected correct behavior?

Should scroll nicely

Relevant logs and/or screenshots

Screen_Recording_2019-10-22_at_15.11.29

(video probably doesn't show how laggy it is)

Possible fixes

A good fix is probably to not show the tooltips when scrolling.