Strange. It works for me on ToT using Linux.
Does it a specific issue to Kevin?

OK. I confirmed it on ToT.
The problem is that the key down event which triggered quick view opening can also subsequently trigger quick view closing.
We should call event.stopImmediatePropagation() in onKeyDownToOpen_.
https://cs.chromium.org/chromium/src/ui/file_manager/file_manager/foreground/js/quick_view_controller.js?q=quick_view_controller&sq=package:chromium&dr&l=205 

Marianne, could you take this? It's awesome if you can add a test to prevent regression.

Test files are located in:
ui/file_manager/integration_tests/file_manager/quick_view.js .
cf. https://chromium-review.googlesource.com/c/chromium/src/+/567910

Started working on it

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/ed36587b63ac296a5a9cd979142574533d8d18c6

commit ed36587b63ac296a5a9cd979142574533d8d18c6
Author: mariannet <mariannet@google.com>
Date: Wed Sep 27 04:08:04 2017

Make sure that folder quick view can be opened reliably.

A race condition sometimes closed the quick view the moment it was opened.
This behavior could be witnessed when rendering the quick view was fast, like
it is for opening folders.
Make sure the <space> key down event only gets handled once (for either opening
or closing) instead of twice, thus eliminating the race condition.
Opening quick view for folders didn't work reliably, fix applied.

Bug:  762699 
Test: manually tested
Cq-Include-Trybots: master.tryserver.chromium.linux:closure_compilation
Change-Id: I899437e312cfa7ad76d45706b670a2db4c83fc48
Reviewed-on: https://chromium-review.googlesource.com/683498
Reviewed-by: Keigo Oka <oka@chromium.org>
Reviewed-by: Naoki Fukino <fukino@chromium.org>
Commit-Queue: Marianne Thieffry <mariannet@google.com>
Cr-Commit-Position: refs/heads/master@{#504577}
[modify] https://crrev.com/ed36587b63ac296a5a9cd979142574533d8d18c6/ui/file_manager/file_manager/foreground/js/quick_view_controller.js

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/23d7fb4389c98a96be6607b72fd58a92d5d11fd8

commit 23d7fb4389c98a96be6607b72fd58a92d5d11fd8
Author: mariannet <mariannet@google.com>
Date: Tue Oct 03 07:46:52 2017

Add a test that opens quick view, closes it, and opens it again on a folder.

Originally, this was supposed to be a regression test for  bug 762699 , but this
test can't detect the bug...
Test that first opens quick view, closes it, then opens it again.

Bug:  762699 
Test: this adds a test
Cq-Include-Trybots: master.tryserver.chromium.linux:closure_compilation
Change-Id: Ib3d8ac961dc4fd57a1ec28e53378a5ba92b073f8
Reviewed-on: https://chromium-review.googlesource.com/683715
Reviewed-by: Naoki Fukino <fukino@chromium.org>
Reviewed-by: Keigo Oka <oka@chromium.org>
Commit-Queue: Marianne Thieffry <mariannet@google.com>
Cr-Commit-Position: refs/heads/master@{#505978}
[modify] https://crrev.com/23d7fb4389c98a96be6607b72fd58a92d5d11fd8/chrome/browser/chromeos/file_manager/file_manager_browsertest.cc
[modify] https://crrev.com/23d7fb4389c98a96be6607b72fd58a92d5d11fd8/ui/file_manager/integration_tests/file_manager/quick_view.js