+oshima, xdai. Split view related?

What version are you seeing this on? What sort of windows does it happen with (apps, browsers, all)?

I cannot reproduce with normal browser windows on 63.0.3239.70 (Official Build) beta (64-bit), so it must have regressed since then.

Seeing it on 64.0.3280.5 dev. Happens on all windows afaict.

Should not be split view related. Split view is only for tablet mode and doesn't respond to Alt+].
Just checked on my device, can not repro it on 65.0.3286.0

abodenha, do you have someone who can dig into this? It's a user-visible regression. It should be bisectable.

I can repro on linux desktop on ToT at r522103

out/Default/chrome --ash-host-window-bounds="1200x800,1250+0-1200x800" --user-data-dir=/w/udd --ash-dev-shortcuts --ash-debug-shortcuts

* Open a single browser window
* Alt-]
* Click in title bar

Interestingly the restored window is positioned under the click point. I suspect it's trying to initiate a drag. Maybe window state changes?

Whoops, didn't mean to -xdai

It seems only emulator reproducible. If so, maybe P2?

I can take a look.

An initial diagnose is:
- on device, only MOUSE_PRESSED event is observed
- on emulator, MOUSE_PRESSED and MOUSE_DRAGGED events are observed

kylechar, maybe ozone/x11 mouse event problem?

Not an ash/wm bug. Resign for a better owner.

It looks like EnterNotify XEvents are being turned into ET_MOUSE_MOVE events instead of ET_MOUSE_ENTERED. The ET_MOUSE_MOVE event becomes ET_MOUSE_DRAGGED because the left mouse button is down.

Turning EnterNotify into ET_MOUSE_MOVE events is intentional. The problem here is that that there is a nested XWindow used by the GPU process. When the user clicks it fires an EnterNotify / LeaveNotify on the nested XWindow.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/ed13853d0fd338f008bcc15495e20c176817bf44

commit ed13853d0fd338f008bcc15495e20c176817bf44
Author: kylechar <kylechar@chromium.org>
Date: Mon Dec 11 17:24:38 2017

Fix synthetic mouse moves in Ozone X11.

When a mouse button is pressed an EnterNotify / LeaveNotify XEvent is
generated for the nested XWindow used by the GPU process. The
EnterNotify ends up becoming a ET_MOUSE_DRAGGED event which is wrong. In
general, we want to just ignore the EnterNotify / LeaveNotify events for
nested XWindows.

Bug:  792322 
Change-Id: I59af57199c0567001256026332823350b4a45d9e
Reviewed-on: https://chromium-review.googlesource.com/819595
Reviewed-by: Sadrul Chowdhury <sadrul@chromium.org>
Commit-Queue: kylechar <kylechar@chromium.org>
Cr-Commit-Position: refs/heads/master@{#523118}
[modify] https://crrev.com/ed13853d0fd338f008bcc15495e20c176817bf44/ui/events/platform/x11/x11_event_source_libevent.cc