Able to reproduce the issue on mac 10.12.6 using latest canary #62.0.3167.0.

Using per revision bisect providing bisect results below

Bisect Information:
--------------------
You are probably looking for a change made after 477477 (known good), but no later than 477478 (first known bad).

Change Log URL: 
-----------------
https://chromium.googlesource.com/chromium/src/+log/a27564e55ec5fd0ff168c23d927c68dec145871c..1406904015cba22c1af48fff00043f44accc4f94

luoe@ - Could you please check whether this is caused with respect to your change, if not please help us in assigning it to the right owner.

Thanks!!

Thanks for the report, this is indeed due to my change.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/b907d9b5de3b32e7bdd6257c7263d5a831737a8b

commit b907d9b5de3b32e7bdd6257c7263d5a831737a8b
Author: Erik Luo <luoe@chromium.org>
Date: Thu Aug 10 02:14:58 2017

DevTools: make SSP filter toolbar visible by sticking to the top

This addresses a regression where the SSP filter bar was not visible when
scrolled down. By adding position: sticky, it now stays at the top of the
container when scrolling.

Behavior is slightly different from what it was before (see right picture),
as the filter bar now smoothly goes out of view when the rules go out of view
when the metrics widget takes up more space.
http://imgur.com/a/XcMlM

Bug:  749008 
Change-Id: I676178d8c06c81b86f0d543e5694bdf3fbbb12ef
Reviewed-on: https://chromium-review.googlesource.com/587891
Reviewed-by: Pavel Feldman <pfeldman@chromium.org>
Commit-Queue: Erik Luo <luoe@chromium.org>
Cr-Commit-Position: refs/heads/master@{#493229}
[modify] https://crrev.com/b907d9b5de3b32e7bdd6257c7263d5a831737a8b/third_party/WebKit/Source/devtools/front_end/elements/stylesSidebarPane.css

Note: Above issue is fixed on latest Canary version: 62.0.3182.0 (Official Build) on Windows,Linux and Mac OS

Thanks you.

Deleted: Actual_dev.mp4 829 KB

	Actual_dev.mp4 829 KB View Download