Can't scroll pages in "Show Applications" when Ubuntu Dock is loaded

[Mubashir Masoodi]

Steps to reproduce:
1. Go to show Application bottom left corner of the windows
2. try to scroll down to check all of the apps.

whenever i try to do the same it doesnt allow me to scroll or check all the apps i have installed

ProblemType: Bug
DistroRelease: Ubuntu 20.04
Package: gnome-control-center 1:3.36.4-0ubuntu2
ProcVersionSignature: Ubuntu 5.8.0-38.43~20.04.1-generic 5.8.18
Uname: Linux 5.8.0-38-generic x86_64
ApportVersion: 2.20.11-0ubuntu27.14
Architecture: amd64
CasperMD5CheckResult: skip
CurrentDesktop: ubuntu:GNOME
Date: Mon Jan 18 18:57:54 2021
InstallationDate: Installed on 2021-01-12 (6 days ago)
InstallationMedia: Ubuntu 20.04.1 LTS "Focal Fossa" - Release amd64 (20200731)
SourcePackage: gnome-control-center
UpgradeStatus: No upgrade log present (probably fresh install)

[Sebastien Bacher (seb128)]

Thank you for the report, how is it failing? Did you try clicking on the other dot on the right of the screen?

[Gunnar Hjalmarsson (gunnarhj)]

I have seen that behavior in a VM, but not in a real install. What kind of installation do you have?

[Daniel van Vugt (vanvugt)]

What kind of input device are you using to scroll?

Also, please open the 'Extensions' app and try disabling 'Ubuntu Dock' and any extra extensions you might have installed. Does that fix the problem? If so then which extension was causing the problem?

[Mubashir Masoodi (mubashirmasoodi)]

i have tried both my laptop mouse pad as well as my external mouse.Further as you suggested that try disabling ubuntu dock,i followed that step and enabled it again that fixed my problem.But can you tell me what caused me this problem as i will try not to do that same next time if it happens and at last i didnt get your #3 point

Thanks for helping me

[Mubashir Masoodi (mubashirmasoodi)]

furthermore when ever i restart the divice the problem remains the same

[Mubashir Masoodi (mubashirmasoodi)]

now i have also uninstalled my extension app from the os

[Daniel van Vugt (vanvugt)]

In order to find out what caused the problem you will need to leave various extensions temporarily disabled/uninstalled. Only then can you be sure which extension was causing the issue.

[Mubashir Masoodi (mubashirmasoodi)]

i have uninstalled all of them including dconf-editor now it is working fine.

[Daniel van Vugt (vanvugt)]

OK, great. Next please try enabling one at a time, like one per day. Then you will be able to find which extension is causing the problem.

[Mubashir Masoodi (mubashirmasoodi)]

yeah sure i will enable them one by one,but is it necessary to enable one per day what if i enable them one by one and check what is causing the issue and report to you the same

[Mubashir Masoodi (mubashirmasoodi)]

furthermore those dots have increased from 3 to 12 but i can navigate only upto 3 pages

[Mubashir Masoodi (mubashirmasoodi)]

one more thing i am currently connected to the broadband via wifi i cannot unable my personal hotspot where can i find the solution

[Daniel van Vugt (vanvugt)]

Yes, if you are confident you have a good test case then try different extensions as quickly as you like.

The problem with too many dots is a separate issue; bug 1889102

And your networking problem is definitely a different problem - you should open a new bug for that.

[Mubashir Masoodi (mubashirmasoodi)]

it is not happening again but i will try my best what is causing this issue and will let you know

[Gunnar Hjalmarsson (gunnarhj)]

I reproduced the issue, i.e. not being able to scroll beyond the first application window in "Show Applications", by installing the 20.04.1 ISO in a VirtualBox VM. I accomplished the installation without downloading upgraded packages, so it was a true vanilla Ubuntu 20.04.1 installation.

Then I updated all packages and rebooted, but the issue was still there.

Then I uninstalled gnome-shell-extension-ubuntu-dock and rebooted, and now the "Show Applications" scrolling worked as expected.

Finally I reinstalled gnome-shell-extension-ubuntu-dock and rebooted, and the issue was back.

So it seems to be something with gnome-shell-extension-ubuntu-dock. Btw, I used an external USB connected mouse.

Shouldn't the importance of this bug be raised? After all it's about a core feature of the Ubuntu desktop.

[Daniel van Vugt (vanvugt)]

Maybe related (from duplicate bug 1914989):

[ 9574.735022] Ubuntu gnome-shell[1681]: Object St.ScrollView (0x5558e598c4c0), has been already deallocated — impossible to access it. This might be caused by the object having been destroyed from C code using something such as destroy(), dispose(), or remove() vfuncs.
[ 9574.743757] Ubuntu gnome-shell[1681]: == Stack trace for context 0x5558e2b27710 ==
[ 9574.799543] Ubuntu gnome-shell[1681]: #0 5558e37610b0 i /<email address hidden>/dash.js:965 (141015fe76a0 @ 132)
[ 9574.801651] Ubuntu gnome-shell[1681]: #1 5558e3761018 i /<email address hidden>/dash.js:494 (141015fec880 @ 30)
[ 9574.801968] Ubuntu gnome-shell[1681]: st_scroll_view_get_vscroll_bar: assertion 'ST_IS_SCROLL_VIEW (scroll)' failed
[ 9574.838268] Ubuntu gnome-shell[1681]: JS ERROR: TypeError: scrollView.get_vscroll_bar(...) is null
                                         ensureActorVisibleInScrollView@/<email address hidden>/dash.js:965:34
                                         _createAppItem/</this._ensureAppIconVisibilityTimeoutId<@/<email address hidden>/dash.js:494:21
[ 9574.839595] Ubuntu gnome-shell[1681]: Object St.Label (0x5558e37f19c0), has been already deallocated — impossible to access it. This might be caused by the object having been destroyed from C code using something such as destroy(), dispose(), or remove() vfuncs.
[ 9574.839845] Ubuntu gnome-shell[1681]: == Stack trace for context 0x5558e2b27710 ==
[ 9574.840822] Ubuntu gnome-shell[1681]: #0 5558e3761138 i /<email address hidden>/appIcons.js:1156 (141015fee970 @ 105)
[ 9574.841718] Ubuntu gnome-shell[1681]: #1 5558e37610a0 i /<email address hidden>/dash.js:41 (141015fe7718 @ 27)
[ 9574.842556] Ubuntu gnome-shell[1681]: #2 5558e3761018 i resource:///org/gnome/shell/ui/dash.js:524 (b5ecd81a448 @ 24)
[ 9574.842720] Ubuntu gnome-shell[1681]: clutter_actor_get_stage: assertion 'CLUTTER_IS_ACTOR (actor)' failed

[Launchpad Janitor (janitor)]

This bug was fixed in the package gnome-shell-extension-ubuntu-dock - 70~ubuntu1

---------------
gnome-shell-extension-ubuntu-dock (70~ubuntu1) impish; urgency=medium

  [ Philipp Kitzberger ]
  * Add new setting: preview size scale

  [ Evan Welsh ]
  * Initial port to GNOME 40.
  * theming: Fix various theming issues
  * Fix showing app icon at the start
  * Use Graphene for indicator rendering.
  * Fix show apps button toggling.
  * Start fixing panel mode...
  * Fix drag and drop and panel mode.
  * Fix workspace scrolling.
  * Fix icon scaling and size changes.
  * Cleanup preferences.
  * More theming and style fixes
  * Convert stylesheet to SCSS.
  * Improve overview animation and styling.
  * Fix regression in panel mode padding.
  * Avoid errors if already tracking the dock
  * Make sassc the default sass compiler
  * Initial fixes for horizontal scrolling.
  * Initial fix for dynamic icon sizing...
  * dash: Fix separator in vertical mode.

  [ Marco Trevisan (Treviño) ]
  * New upstream pre-release (LP: #1912211, LP: #1903582, LP: #1847650)
  * prefs: Port code for the initial size request
  * dash: Do not try to use an invalid value of dragPlaceholderPos
  * cleanup: Remove the unused InjectionsHandler instances
  * utils: Don't store the InjectedFunction on InjectionsHandler
  * utils: Modernize BasicHandler making it possible to use non-array arguments
  * cleanup: Connect to signals with non-array arguments when possible
  * BasicHandler: Support auto-destruction when using a parent Object
  * docking: Avoid recursion on _prepareMainDash()
  * utils: Add PropertyInjectionsHandler to manage property overrides
  * cleanup: Use PropertyInjectionsHandler
  * Utils: Pass the original function to InjectionsHandler callback
  * docking: Replace DashSpacer by overriding ControlsManagerLayout logic
  * docking: Always show the thumbnails box in vertical mode
  * Utils: Add class to inject virtual functions
  * docking: Replace WorkspaceBackground allocation code taking care of the dock
  * docking: Also ignore allocation requests on the original dash
  * Settings: Fix dock size scale selector
  * prefs: Disable monitor selection combo when multi-monitor is enabled
  * theming: Properly parse color from string and set its alpha value
  * theming: Do not try to set the background style with no style
  * prefs: Support running as a standalone application
  * prefs: Use Mutter DBus API to manage per-monitors configuration
  * docking: Properly handle top-positioned dock
  * docking: Use implicit properties features for slide-x
  * docking: Adapt dash(es) startup animation effect to our positioning
  * docking: Do not show the dash before startup animation has completed
  * docking: Use workarea-based allocation in ControlsManagerLayout and
    WorkspaceBackground
  * docking: Adjust overview with vertical auto-hide dock
  * docking: Adjust the AllWorkspaceBox size in secondary monitors
  * docking: Keep cached settings values used during allocation
  * appIcons: Move logic for computing the focused / running state here
  * dash: Fix ensureActorVisibleInScrollView as per upstream changes
  * cleanup: Modernize the code ensureActorVisibleIn...