+jdufault who touched some shelf color stuff recently (unlikely related, but just in case)

Unlikely to be related to what I did, since that's background color and login-shelf, whereas this is just the shelf.

Can't repro on 69.0.3497.21. Probably it's a new regression.

Does it repro for the new shelf?

 Issue 863727  has been merged into this issue.

Yes it repro for the new shelf: https://bugs.chromium.org/p/chromium/issues/detail?id=871897

Issue 871897 has been merged into this issue.

Just to confirm, this is something that was happening before the new shelf, right?

Yep! It's just so pervasive that we think it will be good to fix for M70. :)

Okay, thanks, I was just confirming, just to track down the cause.

Assign to myself.

R69-10758.0.0 has this bug. I will continue bisecting.

Thank you for looking at this!! :-)

Checked R68-10582.0.0, still has this bug.

This might be as msw@ mentioned it is very old bug.

I am thinking the problem might be there is some discrepancy between the touch point/event with the hidden Shelf.

The hidden Shelf received long pressed event while dragging from hidden to visible, however it does not receive the release event, because the touch point is out of the Shelf when releasing. 

+xiyuan@

If Shelf is hidden, when we swipe up, we should not send the event to ShelfView/Button, the ink ripple should not be there.
Maybe some logic in ShelfLayoutManager is wrong [1]
[1] https://cs.chromium.org/chromium/src/ash/shelf/shelf_layout_manager.cc?l=397&rcl=a37b0bc2e31611597140b8e3256978b993bff6ec

Discussed with newcomer@ and sammiequon@, found the root cause.
newcomer@ will have a fix soon.
Assign this to newcomer@.

I have a fix for this. I'll have it cleaned up by tomorrow.

It also seems like we can launch apps when the shelf is hidden. I showed ux and we all agreed that although it's pretty cool, we should fix it. I'll fix this in the same CL.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/8f1c1ed63cb9c8acc5617b049abba5874aecc0cc

commit 8f1c1ed63cb9c8acc5617b049abba5874aecc0cc
Author: Alex Newcomer <newcomer@chromium.org>
Date: Fri Aug 31 18:55:59 2018

cros: Don't process events on app icons while the shelf is hidden.

2 bug fixes.
1. Fix swiping up on the auto-hidden shelf from interacting with
   ShelfButtons.
2. Prevent users from accidentally activating ShelfButtons by tapping
   the bottom of the screen while the shelf is autohidden.

Bug:  872854 
Change-Id: I5376eac2b7090b6109ad28cb0e9dfc4a748343e6
Reviewed-on: https://chromium-review.googlesource.com/1198522
Commit-Queue: Alex Newcomer <newcomer@chromium.org>
Reviewed-by: Sammie Quon <sammiequon@chromium.org>
Reviewed-by: Xiyuan Xia <xiyuan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#588101}
[modify] https://crrev.com/8f1c1ed63cb9c8acc5617b049abba5874aecc0cc/ash/shelf/shelf_layout_manager.cc

Your change meets the bar and is auto-approved for M70. Please go ahead and merge the CL to branch 3538 manually. Please contact milestone owner if you have questions.
Owners: benmason@(Android), kariahda@(iOS), geohsu@(ChromeOS), abdulsyed@(Desktop)

For more details visit https://www.chromium.org/issue-tracking/autotriage - Your friendly Sheriffbot

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/521875c7b4a87b8f8196fbbddae4b8cd416306ac

commit 521875c7b4a87b8f8196fbbddae4b8cd416306ac
Author: Alex Newcomer <newcomer@chromium.org>
Date: Mon Sep 10 23:14:35 2018

cros: Don't process events on app icons while the shelf is hidden.

2 bug fixes.
1. Fix swiping up on the auto-hidden shelf from interacting with
   ShelfButtons.
2. Prevent users from accidentally activating ShelfButtons by tapping
   the bottom of the screen while the shelf is autohidden.

TBR=newcomer@chromium.org

(cherry picked from commit 8f1c1ed63cb9c8acc5617b049abba5874aecc0cc)

Bug:  872854 
Change-Id: I5376eac2b7090b6109ad28cb0e9dfc4a748343e6
Reviewed-on: https://chromium-review.googlesource.com/1198522
Commit-Queue: Alex Newcomer <newcomer@chromium.org>
Reviewed-by: Sammie Quon <sammiequon@chromium.org>
Reviewed-by: Xiyuan Xia <xiyuan@chromium.org>
Cr-Original-Commit-Position: refs/heads/master@{#588101}
Reviewed-on: https://chromium-review.googlesource.com/1217908
Reviewed-by: Alex Newcomer <newcomer@chromium.org>
Cr-Commit-Position: refs/branch-heads/3538@{#255}
Cr-Branched-From: 79f7c91a2b2a2932cd447fa6f865cb6662fa8fa6-refs/heads/master@{#587811}
[modify] https://crrev.com/521875c7b4a87b8f8196fbbddae4b8cd416306ac/ash/shelf/shelf_layout_manager.cc

 Issue 750237  has been merged into this issue.