@Reporter:Tried checking the issue with the given JSbin URL, the issue is reproducible on the reported chrome version 61.0.3163.91, and as it works fine in M50 (50.0.2652.0) , we started bisecting, but the JSbin URL provided by you is not working fine with few chrome versions to check the issue, Could you please provide another JSbin file/Url to confirm the issue.

Thanks!

The issue implies using native Shadow DOM v1.

As far as I know, Shadow DOM v1 support was first introduced in Chrome 53. Therefore it does not really make sense to try anything older. The exact behaviour of the demo in the browsers lacking native Shadow DOM v1 support does not matter.

Currently I do not see any errors in the demo itself to fix. I have tried this demo with different native Shadow DOM v1 implementation in Safari 11, it works as expected there.

Thank you for providing more feedback. Adding requester "vamshi.kommuri@techmahindra.com" to the cc list and removing "Needs-Feedback" label.

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

Please note that, as of this moment, JSbin seems to be temporarily out of service. It does not even start a new bin for me. This might be a reason why the JSbin demo is not working in some Chrome versions for you as well.

Since the test file for this is no longer working to repro the issue and as per Comment#2 this seems to be happening since in Chrome 53 when Shadow DOM v1 support was first introduced. Adding proper component and cc'ing devs @hayato and @kochi for more inputs on this.

As JSbin is down, I have created a repro in JSfiddle as well: https://jsfiddle.net/fLuznvv7/1/

This seems editing selection issue.

Yoichi, could you take a look?

Able to reproduce this issue on reported version 61.0.3163.91 and latest Canary 63.0.3238.0 using Win 10, Ubuntu 14.04 and Mac 10.12.6


Bisect Information:
====================
Good build: 60.0.3104.0   -Revision :473014
Bad Build: 60.0.3105.0     -Revision:473393

Unable to perform per-revision bisect on M60, hence providing chromium bisect changelog

You are probably looking for a change made after 473127 (known good), but no later than 473131 (first known bad).
CHANGELOG URL:
  https://chromium.googlesource.com/chromium/src/+log/dac8e43d7961d3bd5d4db36b191aecd64e0979c9..99c24962dc687afd137ce69f7efb0a4ae1367301

Suspecting:
https://codereview.chromium.org/2891693002

@yosin:  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!

Mark WontFix since this is expected behavior.

To set focus into distributed element, please add tabindex="0" to distributed
element, in the sample in #c1:
<my-container>
  <div tabindex="0">Slotted element. Try to start a selection here.</div>
_______^^^^^^^^^^^^
</my-container>

In the sample #c1, default event handler of "mousedown" set focus to BODY then
JS timer attempts to set focus to |focusable| and cancel mouse dragging since
active element is moved.