I am also getting an unintended result (though possibly a bit different from yours).

When I do these steps the first click of the launcher button does nothing and then on the second click the launcher appears on a small subset of the external display (screenshot attached).

Moreover if instead of step (3), I click the launcher button on the external display, the first click again does nothing, and on the second click the launcher flashes really quickly on the internal display and then disappears.

I also reproduced this on a Link and on 61.0.3163.13 dev so the bug is likely a Launcher-related bug that was introduced at / before that build. Passing this on to Alex and CC-ing Vadim

Deleted: Screenshot 2017-08-03 at 9.40.29 AM - Display 1.png 1.9 MB

	Screenshot 2017-08-03 at 9.40.29 AM - Display 1.png 1.9 MB View Download

 Issue 740617  has been merged into this issue.

 Issue 754450  has been merged into this issue.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/c9b5364ee619ec0aa24c7dbc087652c331b09769

commit c9b5364ee619ec0aa24c7dbc087652c331b09769
Author: Weidong Guo <weidongg@chromium.org>
Date: Sat Aug 12 01:19:15 2017

Support fullscreen app list in extended monitor

Changes:
1. Use Window::SetBoundsInScreen and Window::SetBounds instead of
Widget::SetBounds which smartly show the widget only in the display
where it has the largest intersection.
2. Unify all points and rectangles in drag to using screen coordinates
to avoid weird movement in extended monitor.
3. Reset the initial drag point only when we are not in drag.

BUG= 752166 

Change-Id: Ic42107991ec3007a640f851396f6a68fcbf142c3
Reviewed-on: https://chromium-review.googlesource.com/610889
Commit-Queue: Weidong Guo <weidongg@chromium.org>
Reviewed-by: Xiyuan Xia <xiyuan@chromium.org>
Reviewed-by: Dan Erat <derat@chromium.org>
Cr-Commit-Position: refs/heads/master@{#493925}
[modify] https://crrev.com/c9b5364ee619ec0aa24c7dbc087652c331b09769/ui/app_list/presenter/app_list_presenter_impl.cc
[modify] https://crrev.com/c9b5364ee619ec0aa24c7dbc087652c331b09769/ui/app_list/views/app_list_view.cc
[modify] https://crrev.com/c9b5364ee619ec0aa24c7dbc087652c331b09769/ui/app_list/views/app_list_view.h

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/e5f7f5a7f8b099c385bfe00bffa469f46f98adc0

commit e5f7f5a7f8b099c385bfe00bffa469f46f98adc0
Author: Maajid <maajid@chromium.org>
Date: Thu Aug 17 01:12:20 2017

Support fullscreen app list in extended monitor

Changes:
1. Use Window::SetBoundsInScreen and Window::SetBounds instead of
Widget::SetBounds which smartly show the widget only in the display
where it has the largest intersection.
2. Unify all points and rectangles in drag to using screen coordinates
to avoid weird movement in extended monitor.
3. Reset the initial drag point only when we are not in drag.

BUG= 752166 
TBR=weidongg@chromium.org

(cherry picked from commit c9b5364ee619ec0aa24c7dbc087652c331b09769)

Change-Id: Ic42107991ec3007a640f851396f6a68fcbf142c3
Reviewed-on: https://chromium-review.googlesource.com/610889
Commit-Queue: Weidong Guo <weidongg@chromium.org>
Reviewed-by: Xiyuan Xia <xiyuan@chromium.org>
Reviewed-by: Dan Erat <derat@chromium.org>
Cr-Original-Commit-Position: refs/heads/master@{#493925}
Reviewed-on: https://chromium-review.googlesource.com/618400
Reviewed-by: Vadim Tryshev <vadimt@chromium.org>
Cr-Commit-Position: refs/branch-heads/3163@{#622}
Cr-Branched-From: ff259bab28b35d242e10186cd63af7ed404fae0d-refs/heads/master@{#488528}
[modify] https://crrev.com/e5f7f5a7f8b099c385bfe00bffa469f46f98adc0/ui/app_list/presenter/app_list_presenter_impl.cc
[modify] https://crrev.com/e5f7f5a7f8b099c385bfe00bffa469f46f98adc0/ui/app_list/views/app_list_view.cc
[modify] https://crrev.com/e5f7f5a7f8b099c385bfe00bffa469f46f98adc0/ui/app_list/views/app_list_view.h