The reason for that is after the notification bar floats down we refocus on the omnibox. However, omnibox is not part of the webpage but page of the browser. So, unless you work on other applications, you will be forced to focus back to that new tab page's omnibox even when you were in the middle of something on another page. One way to fix this is that we will not focus on the omnibox after the notification bar disappear unless the user interactive any buttons on the notification bar. Like clicking or hitting enter on "Undo" OR "Restore". wdyt?

Is this platform-specific? I couldn't replicate it on 71.0.3550.0 / Mac.

Yes, I believe so. I can't reproduce on my Mac either, but it is reproducible on Linux.

Thanks! Removing Mac label. Let's check if it occurs on Windows too.

Also, is there anything specific with incognito windows here, or does this happen with any window?

This will happen with any window as long as it's not the same window as the one with the float bar. This change also introduce a weird behavior on  crbug.com/883228 .

Regarding comment #1: I think it makes sense to apply focus after the notification toast pops up if the current tab is active, regardless of whether the user has interacted with any items on the notifications toast. If they've interacted with the notification, focus moves immediately anyway, so they wouldn't get into the scenario with this incognito window (I think!).

Update: This will also happen on Windows.

 Issue 883228  has been merged into this issue.

@c7: this wouldn't fix the disruption to a user typing text somewhere else like in  crbug.com/883228 . I think we should probably just do as Weilun suggest in c1.

@c10: That's fair. It'll just mean that there's only a partial fix for  crbug.com/873978 .

Yep, agreed.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/4c56a2e09b12195ce4a9e4eb6b592d089941c008

commit 4c56a2e09b12195ce4a9e4eb6b592d089941c008
Author: Weilun Shi <sweilun@chromium.org>
Date: Fri Sep 14 00:43:45 2018

[NTP] Refocus on omnibox only when user clicks the undo/restore button

Refocusing on the omnibox only when user clicks any buttons on the
notification bar. In that way, we can make sure that the user is
interacting with that new tab. Bluring the buttons on the notification
bar if user don't do anything to make sure we will not focus on the
hidden item.

Bug:  882335 
Change-Id: I2310e1318764f8cae77ce59155164cbf14233324
Reviewed-on: https://chromium-review.googlesource.com/1222871
Commit-Queue: Weilun Shi <sweilun@chromium.org>
Reviewed-by: Kristi Park <kristipark@chromium.org>
Cr-Commit-Position: refs/heads/master@{#591235}
[modify] https://crrev.com/4c56a2e09b12195ce4a9e4eb6b592d089941c008/chrome/browser/resources/local_ntp/local_ntp.js

Update :
---------
Tested above issue in Canary build #71.0.3554.0 on Windows(7, 8, 8.1, 10), Linux(14.04 LTS) OS and the issue is fixed. 
Hence adding TE-Verified labels. Kindly review an attached screen-cast for reference.
Thank You.

Deleted: Fixed_Behaviour.mp4 875 KB

	Fixed_Behaviour.mp4 875 KB View Download