Archives For Howtos

gThumb, GNOME image viewer and organizer, released version 3.11.3 a few days ago. Here’s how to install it in Ubuntu 20.04, Ubuntu 18.04, Ubuntu 20.10 via PPA.

gThumb 3.11.3 adds support for JPEG XL – the next generation image coding standard.

JPEG XL (.jxl) is based on ideas from Google’s Pik format and Cloudinary’s FUIF format. It is the next-generation, general-purpose image compression codec by the JPEG committee. Some popular apps, e.g., ImageMagick, XnView MP, have already added support for the image format.

gThumb now opens the .jxl image format through the libjxl library.

Other changes in the release include:

  • Added file actions to the viewer context menu.
  • Removed facebook and picasaweb uploaders
  • Fixed issue that continuously reloads image when it is only image in folder
  • Webp can have transparency as well.
  • New and updated translations.

How to Install gThumb 3.11.3 in Ubuntu via PPA:

For Ubuntu 18.04 (64-bit), Ubuntu 20.04, Ubuntu 20.10, Ubuntu 21.04, Linux Mint 19.x, 20.x, you can install the new release packages via the unofficial PPA.

NOTE for Ubuntu 21.04: It seems to have bug (not sure) in libjxl when building against Clang 11.0.1. So gThumb packge for 21.04 was built without JPEG XL support.

1.) To add the PPA, open terminal from system application launcher, and run command:

sudo add-apt-repository ppa:ubuntuhandbook1/apps

2.) You can then either upgrade the image viewer from an old version via Update Manager (Software Updater), or run command in terminal:

sudo apt install gthumb

Uninstall gThumb & the Ubuntu PPA

To remove gThumb image viewer, run command:

sudo apt remove --autoremove gthumb gthumb-data

To remove the Ubuntu PPA, either run the apt-add-repository command with --remove flag, or use Software & Updates -> Other Software.

Use GVfs admin backend to open Nautilus file browser or Gedit text editor with root permission? It’s not working in Ubuntu 21.04.

When you run nautilus admin:// or gedit admin:// to open folder or document with root, it won’t work and output an error:

GDBus.Error:org.freedesktop.PolicyKit1.Error.Failed: Unix process subject does not have uid set

The error also occurs when using nautilus-admin extension to enable ‘open as root’ context menu.

The issue is caused by a gvfs commit to fix flatpak app network permission requirement problem. To get rid of the error (see bug), reverting just that one commit could be a workaround.

Method 1: Install old GVfs from Ubuntu 20.10 repository:

You can download & install the gvfs .deb packages for the previous Ubuntu 20.10. And here are the links for 64-bit system:







Grab the 6 packages, then open terminal (Ctrl+Alt+T) and run command to install all of them:

sudo apt install ./Downloads/gvfs*.deb

Method 2: repack GVfs to revert the commit:

If you don’t want to downgrade gvfs, just rebuild it without the commit. To make things easy, I’ve uploaded into this PPA.

1. Open terminal either from system app launcher or by pressing Ctrl+Alt+T on keyboard. When it opens, run command to add the PPA:

sudo add-apt-repository ppa:ubuntuhandbook1/gvfs

2. Then install the patched version of gvfs via command:

sudo apt install gvfs=1.47.91-2ubuntu1

3. Finally remove the PPA via command:

sudo add-apt-repository --remove ppa:ubuntuhandbook1/gvfs

How to Restore GVfs to stock version:

If you change mind, and want to revert it back, simply run command in terminal:

sudo apt install gvfs=1.47.91-1ubuntu1

Want to get Google search suggestions in your system search results? There’s now an extension to enable the feature in Gnome Desktop.

Google Search Provider is the extension inspired by DuckDuckGo Search Provider. With it, typing any keyword in the Activities overview or ‘Show Applications’ search box will display Google search suggestions. And you can click to open the result in your favorite web browser.

How to Install the Extension in Ubuntu:

The Gnome Shell extension so far supports Gnome 3.36 & 3.38, so it should work in Ubuntu 20.04, Ubuntu 20.10, and the upcoming Ubuntu 21.04.

1.) Firstly open terminal (Ctrl+Alt+T) and run command to install the chrome-gnome-shell package if you don’t have it:

sudo apt install chrome-gnome-shell

2.) Next go to the extension web page in web browser, and turn on the toggle icon to install it.

If you don’t see the toggle icon, click the link “Click here to install browser extension” and refresh the web page afterward.

Uninstall Gnome Shell Extension

To remove the extension, either go to the web page again or use Extensions tool, which can be installed via sudo apt install gnome-shell-extension-prefs command.

Want to try out the new Gnome 40 Desktop? You can install it in Ubuntu 21.04 Hirsute Hippo via PPA.

Gnome 40 was released more than a week ago with new features including new design for the overview screen, a horizontal workspace switcher, Dock at the bottom, new gestures, and more.

While Ubuntu 21.04 includes Gnome 3.38.x with some Gnome 40 core applications, you can get the new desktop environment via this third-party PPA.

WARNING: GNOME 40 is not yet officially supported in Ubuntu 21.04. The PPA packages is just for testing purpose! Use it at your own risk!

1.) Firstly open terminal by pressing Ctrl+Alt+T on keyboard. When it opens, run command to add the PPA:

sudo add-apt-repository ppa:shemgp/gnome-40

Type your user password (no asterisk feedback) when it asks and hit Enter to continue.

2.) After adding the PPA, run command to upgrade the mutter window manager:

sudo apt install mutter

You can follow the command in the PPA description, which adds the package version in the code. It however just works with the package name only.

3.) Then install Gnome Shell 40 via command:

sudo apt install gnome-shell

4.) As the default Yaru theme is not updated for Gnome 40, you have to install and use Gnome Session instead of the Ubuntu Session. To install it, run command:

sudo apt install gnome-session

5.) And run command for the rest packages:

sudo apt upgrade

Finally reboot your machine. When you’re in login screen, DO SELECT “Gnome” or “Gnome on Xorg” before logging in. To do so, select your user and then click the gear button in the bottom-right and select Gnome in popup menu.

How to Uninstall Gnome 40:

To remove the new Gnome Desktop and revert back to the original v3.38.x, run command to purge the Ubuntu PPA:

sudo apt install ppa-purge && sudo ppa-purge ppa:shemgp/gnome-40

And if you no longer use the Gnome Session from login screen, remove it via command:

sudo apt remove gnome-session

Prefer the light mode appearance? Here’s how to change the system tray menu, date & time menu, notifications, and other top panel drop-down menus from dark to light in Ubuntu 21.04.

Different to previous Ubuntu releases, Ubuntu 21.04 now has top-panel menus in dark mode. It’s good for those prefer the dark themes. However, light mode fans need to change the Gnome Shell theme to get better experience.



1. Install User Themes Extension:

To get started, you have to first install the User Themes Gnome Shell extension, which enables ability to change the Gnome Shell Theme.

Method 1: Install the extension via single command:

Press Ctrl+Alt+T on keyboard to bring up a terminal window and run the command below will install a dozen of extensions, including User Themes, in Ubuntu:

sudo apt install gnome-shell-extensions

Once installed, log out and back in.

Method 2: Install the extension from

For clean freak just need the single extension, firstly install chrome-gnome-shell package via command:

sudo apt install chrome-gnome-shell

Then click to go to the extension web page and turn on the toggle icon to install the extension.

Don’t see the toggle icon? Click ‘Click here to install browser extension’ to install browser extension, and then refresh the web page.

2. Change Gnome Shell Theme:

After installed User Themes extension, launch Gnome Tweaks (install it from Ubuntu Software) and go to Extensions tab.

There scroll down, find out and turn on the extension, click the gear button to get into settings. And finally select Yaru-light or gnome classic for even light top panel.

That’s it. Enjoy!