Tenders McChiken's questions

I use a laptop from linovo where they replaced the Menu key with PrtScn. I restored the menu key through XKB - which fortunately still works with Wayland Gnome - but lost the dedicated print-screen key as a result. See this question for a picture of the problem.

To get around the lack of a PrtScn key, I used to run gnome-screenshot -i from the terminal. Unfortunately, this command was removed in whatever version of Gnome that shipped with Ubuntu 22.04. I tried guessing the command in Gnome's "Run a Command" dialog (i.e Alt+F2`) with little success.

How do access the screenshot functionality in modern versions of gnome without using the dedicated keyboard key?

I run ubuntu on several internet-facing servers.

I recently discovered that the official ubuntu mirror I was using was severely out of date; When I changed my sources and updated apt, I was surprised with about half a gigabyte's worth of packages that were outdated and in need of updating. Among those packages were apt, linux-base and other packages that I assume are integral to the security of my systems. This confused me because I had assumed that security updates were directly fetched from security.ubuntu.com.

Because of this, I want to ask the following questions:

1. Does Ubuntu rely on the "freshness" of the primary mirror for its security in any way? Or stated in another way: Can an outdated non-security mirror impede or ubstruct Ubuntu's ability to update itself in any way?

2. Does the *-security repository contain every single security update issued by canonical during a distribution's lifetime?

Edit 2019-10-29: As requested, here is the sources.list from one of the servers. Note that this the stock file that came with ubuntu. The only change was replacing the urls of the outdated mirror with archive.ubuntu.com. I also took the liberty to limit the scope of my question by breaking it into a small set of simple yes-no questions.

# 

# deb cdrom:[Ubuntu-Server 18.04.2 LTS _Bionic Beaver_ - Release amd64 (20190210)]/ bionic main restricted

#deb cdrom:[Ubuntu-Server 18.04.2 LTS _Bionic Beaver_ - Release amd64 (20190210)]/ bionic main restricted

# See http://help.ubuntu.com/community/UpgradeNotes for how to upgrade to
# newer versions of the distribution.
deb http://archive.ubuntu.com/ubuntu/ bionic main restricted
# deb-src http://archive.ubuntu.com/ubuntu/ bionic main restricted

## Major bug fix updates produced after the final release of the
## distribution.
deb http://archive.ubuntu.com/ubuntu/ bionic-updates main restricted
# deb-src http://archive.ubuntu.com/ubuntu/ bionic-updates main restricted

## N.B. software from this repository is ENTIRELY UNSUPPORTED by the Ubuntu
## team. Also, please note that software in universe WILL NOT receive any
## review or updates from the Ubuntu security team.
deb http://archive.ubuntu.com/ubuntu/ bionic universe
# deb-src http://archive.ubuntu.com/ubuntu/ bionic universe
deb http://archive.ubuntu.com/ubuntu/ bionic-updates universe
# deb-src http://archive.ubuntu.com/ubuntu/ bionic-updates universe

## N.B. software from this repository is ENTIRELY UNSUPPORTED by the Ubuntu 
## team, and may not be under a free licence. Please satisfy yourself as to 
## your rights to use the software. Also, please note that software in 
## multiverse WILL NOT receive any review or updates from the Ubuntu
## security team.
deb http://archive.ubuntu.com/ubuntu/ bionic multiverse
# deb-src http://archive.ubuntu.com/ubuntu/ bionic multiverse
deb http://archive.ubuntu.com/ubuntu/ bionic-updates multiverse
# deb-src http://archive.ubuntu.com/ubuntu/ bionic-updates multiverse

## N.B. software from this repository may not have been tested as
## extensively as that contained in the main release, although it includes
## newer versions of some applications which may provide useful features.
## Also, please note that software in backports WILL NOT receive any review
## or updates from the Ubuntu security team.
deb http://archive.ubuntu.com/ubuntu/ bionic-backports main restricted universe multiverse
# deb-src http://archive.ubuntu.com/ubuntu/ bionic-backports main restricted universe multiverse

## Uncomment the following two lines to add software from Canonical's
## 'partner' repository.
## This software is not part of Ubuntu, but is offered by Canonical and the
## respective vendors as a service to Ubuntu users.
# deb http://archive.canonical.com/ubuntu bionic partner
# deb-src http://archive.canonical.com/ubuntu bionic partner

deb http://security.ubuntu.com/ubuntu bionic-security main restricted
# deb-src http://security.ubuntu.com/ubuntu bionic-security main restricted
deb http://security.ubuntu.com/ubuntu bionic-security universe
# deb-src http://security.ubuntu.com/ubuntu bionic-security universe
deb http://security.ubuntu.com/ubuntu bionic-security multiverse
# deb-src http://security.ubuntu.com/ubuntu bionic-security multiverse

How can I spellcheck text files that contain Arabic text? The answer in Adding languages to gedit spellchecker recommends installing a myspell dictionary, but no such dictionary seems to exist for this particular language (at least not in the official apt repositories).

I'm using Ubuntu 18.04 and have used GNOME Tweaks(1) to restore normal keyboard layout switching behavior where pressing Alt+Shift cycles between enabled layouts. I've also used Gnome Settings(2) in an attempt to restore normal windows switching where Alt+Tab brings up a list of windows and moves the selected window from the most recently-used window to the least, and Shift+Alt+Tab moves the cursor in the opposite direction.

Keyboard layout works well. Window switching does not: Alt+Tab behaves as expected but Shift+Alt+Tab does not because it changes the keyboard layout rather than traverse the window list.

How can I restore normal Shift+Alt+Tab functionality when using multiple layouts? I know it's possible because I've read a blog post on how to do it once, however I was unable to find said blog post again.

Edit: Found it! See: https://www.guyrutenberg.com/2015/10/02/gnome-altshift-and-altshifttab/

Edit2: I believe this is not a duplicate of OS keyboard shortcuts conflict with apps keyboard shortcuts in GNOME 3 because it's specific to Shift+Alt and that specificity seems to have allowed for an acceptable workaround. See my answer below.

Notes:

1. The setting is under Tweaks > Keyboard & Mouse > Additional Layout Options.
2. Normal Keyboard Shortcut reassignment.