"Show Applications" button triggers too often on touchscreen

[Peter Bittner]

Given I am logged in on the Ubuntu default desktop (running GNOME Shell 3.28.1)
when I press the "Show Applications" button at the lower end of the task bar
then only the tooltip appears
and when I press the "Show Applications" button again
then the applications (of the "Frequent" category) are shown and immediately hidden again.

Extended scenario:

When the above described has been done a few times
then pressing the "Show Applications" button _only once_ makes the applications show _and_ hide immediately (in a single action)
and I have to use the mouse to make the applications display.

Current Behavior
----------------

It looks like touch screen events for that area are somewhat "recorded" and then executed all at once.

Expected Behavior
-----------------

The applications should be shown immediately upon a single touch press on the "Show Applications" button, and hidden again the same way. In other words, the behavior should be consistent with pressing the button using the mouse (or touch pad).

Additional Information
----------------------

I could reproduce this issue on both a Dell Inspiron 13 5000 Series 2-in-1 (convertible with touch screen) and a Lenovo X1 Carbon 6th Generation (2018).

ProblemType: Bug
DistroRelease: Ubuntu 18.04
Package: gnome-shell 3.28.1-0ubuntu1
ProcVersionSignature: Ubuntu 4.15.0-15.16-generic 4.15.15
Uname: Linux 4.15.0-15-generic x86_64
ApportVersion: 2.20.9-0ubuntu5
Architecture: amd64
CurrentDesktop: ubuntu:GNOME
Date: Thu Apr 19 11:18:53 2018
DisplayManager: gdm3
GsettingsChanges:
 b'org.gnome.shell' b'enabled-extensions' b"['<email address hidden>', '<email address hidden>', '<email address hidden>', '<email address hidden>', 'docker_status@gpouilloux', '<email address hidden>', '<email address hidden>', 'OverviewAllWindows@amiller27', '<email address hidden>', '<email address hidden>']"
 b'org.gnome.shell' b'enable-hot-corners' b'true'
 b'org.gnome.shell' b'favorite-apps' redacted by apport
 b'org.gnome.desktop.interface' b'gtk-im-module' b"'gtk-im-context-simple'"
 b'org.gnome.desktop.interface' b'show-battery-percentage' b'true'
InstallationDate: Installed on 2018-04-06 (13 days ago)
InstallationMedia: Ubuntu 18.04 LTS "Bionic Beaver" - Alpha amd64 (20180403)
SourcePackage: gnome-shell
UpgradeStatus: No upgrade log present (probably fresh install)

[Aurélien (titou829)]

I also encounter the same problem.
From my point of view it seems that when I press the touch screen it generates two simple clicks. That's why when I click the "Show application" it opens and immediately close the application list. Moreover when I click on another application shortcut it opens the application twice.

Under ubuntu 17 I had this bug only with xorg not xwayland. Since I upgraded to 18.04 I encounter the problem in both xorg and xwayland.

When I check the events generated when I quickly press the screen libinput-debug-events returns only: "TOUCH_DOWN, TOUCH_FRAME, TOUCH_UP, TOUCH_FRAME" events which seems to be normal.

Thus I guess that the bug might comes from the Gnome framework.

My laptop is a 2-in-1 ASUS T304UA.

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[ragtag (ragtag-ragtag)]

This same bug affects me on Ubuntu 18.04 on a ThinkPad Yoga 12 (S120). It double clicks all the icons in the launcher, so if I for instance select Nautilus, it will open two Nautilus windows. As a workaround, I was able to touch Activities, and then the application launcher, and it would open correctly.

[AlpineCarver (acarv)]

I am getting exactly the same behavior, running Ubuntu 18.04 LiveCD on a Dell Venue 11 Pro 7140.

Using the touchscreen to click an icon in the dash results in TWO instances of the given application being created.

Using the touchscreen to click the "Show Applications" icon does nothing

[Peter Bittner (peter-bittner)]

Can we escalate this issue somehow? Where does it have to be fixed? Upstream?

What about certification? Can that help to escalate the issue?

- https://certification.ubuntu.com/hardware/201712-26045/ (ThinkPad X1 Carbon 6th Generation)
- https://certification.ubuntu.com/hardware/201603-20841/ (Dell Inspiron 13 2-in-1 5000 Series)
- https://certification.ubuntu.com/hardware/201605-22328/ (Dell Inspiron 13 2-in-1 5000 Series)
- No certification yet for ASUS T304UA 2-in-1
- No certification yet for ThinkPad Yoga 12 (S120)
- No certification yet for Dell Venue 11 Pro 7140

The problem seems generic to touch screen devices in general. As long as this isn't fixed the GNOME desktop (and thus Ubuntu) isn't ready for devices equipped with touch screens, including the popular 2-in-1 convertibles.

[Daniel van Vugt (vanvugt)]

Yes. To escalate the issue please report it to the Gnome developers here:

  https://gitlab.gnome.org/GNOME/gnome-shell/issues

and then tell us the new bug ID.

[Peter Bittner (peter-bittner)]

GNOME Shell bug #480 created, https://gitlab.gnome.org/GNOME/gnome-shell/issues/480

[Peter Bittner (peter-bittner)]

Here is their answer:

> The default Ubuntu session is not upstream GNOME. In particular
> the dash is replaced with a Unity-style dock, so please test
> with the non-default "pure GNOME" session first.

Can the team at Canonical that deals with the Unity-style dock verify the behavior is not introduced by their code?

[Daniel van Vugt (vanvugt)]

Sorry, I forgot the Ubuntu dock is a separate component.

Now I look at the Ubuntu dock bugs this sounds like bug 1730281, which is presently marked as a duplicate of bug 1725384. So this bug should probably be merged with those.