After many years of working with Ubuntu, I finally installed Ubuntu Mate desktop as I was recommended.
At the moment I cannot manage to active the following keyboard shortcuts, which were very useful for me till now:
Take a selected-area screenshot:
The shift+ImpPt (PrtScn) combination opens a 'take screenshot' pop-up which allows me to perform this action.
However, I used to have a shortcut which opened directly the area screenshot cursor, now with this combination I have to perform another step.
Change keyboard layout:
In System->Preferences->Hardware->keyboard, under the layout tab, I found the "Options..." button than has inside the item "Switching to another layout". I tried a couple of combinations but it doesn't work for me (Alt+Shift, Ctrl+Shift, ...).
Just to be clear, I am lookign for a shortcut that will toggle between 3 different layouts I have.
============= Edit ===========
More information:
$ cat /etc/default/keyboard
XKBLAYOUT=es,gb,il
XKBVARIANT=,,
BACKSPACE=guess
$ dpkg -l | grep ibus
ii gir1.2-ibus-1.0:amd64 1.5.22-2ubuntu2.1 amd64 Intelligent Input Bus - introspection data
ii ibus 1.5.22-2ubuntu2.1 amd64 Intelligent Input Bus - core
ii ibus-data 1.5.22-2ubuntu2.1 all Intelligent Input Bus - data files
ii ibus-gtk:amd64 1.5.22-2ubuntu2.1 amd64 Intelligent Input Bus - GTK2 support
ii ibus-gtk3:amd64 1.5.22-2ubuntu2.1 amd64 Intelligent Input Bus - GTK3 support
ii ibus-table 1.9.25-1 all table engine for IBus
ii libgusb2:amd64 0.3.4-0.1 amd64 GLib wrapper around libusb1
ii libibus-1.0-5:amd64 1.5.22-2ubuntu2.1 amd64 Intelligent Input Bus - shared library
ii libusageenvironment3:amd64 2020.01.19-1build1 amd64 multimedia RTSP streaming library (UsageEnvironment classes)
ii libusb-1.0-0:amd64 2:1.0.23-2build1 amd64 userspace USB programming library
ii libusbmuxd6:amd64 2.0.1-2 amd64 USB multiplexor daemon for iPhone and iPod Touch devices - library
ii python3-ibus-1.0 1.5.22-2ubuntu2.1 all Intelligent Input Bus - introspection overrides for Python (Python 3)
$ gsettings list-recursively | grep xkb
org.mate.peripherals-keyboard-xkb.general default-group -1
org.mate.peripherals-keyboard-xkb.general known-file-list @as []
org.mate.peripherals-keyboard-xkb.general disable-sysconfig-changed-warning false
org.mate.peripherals-keyboard-xkb.general update-handlers @as []
org.mate.peripherals-keyboard-xkb.general group-per-window true
org.mate.peripherals-keyboard-xkb.general duplicate-leds false
org.mate.peripherals-keyboard-xkb.general disable-indicator false
org.mate.peripherals-keyboard-xkb.general layout-names-as-group-names true
org.mate.peripherals-keyboard-xkb.general load-extra-items false
org.mate.peripherals-keyboard-xkb.general handle-indicators false
org.gnome.desktop.input-sources xkb-options @as []
org.gnome.desktop.input-sources sources [('xkb', 'es'), ('xkb', 'gb'), ('xkb', 'il')]
org.mate.peripherals-keyboard-xkb.kbd layouts @as []
org.mate.peripherals-keyboard-xkb.kbd options @as []
org.mate.peripherals-keyboard-xkb.kbd model ''
org.freedesktop.ibus.panel xkb-icon-rgba '#415099'
org.mate.peripherals-keyboard-xkb.indicator show-flags false
org.mate.peripherals-keyboard-xkb.indicator background-color ''
org.mate.peripherals-keyboard-xkb.indicator font-family ''
org.mate.peripherals-keyboard-xkb.indicator foreground-color ''
org.mate.peripherals-keyboard-xkb.indicator secondary 0
org.mate.peripherals-keyboard-xkb.preview width -1
org.mate.peripherals-keyboard-xkb.preview y -1
org.mate.peripherals-keyboard-xkb.preview height -1
org.mate.peripherals-keyboard-xkb.preview x -1
org.freedesktop.ibus.general xkb-latin-layouts ['ara', 'bg', 'cz', 'dev', 'gr', 'gur', 'in', 'jp(kana)', 'mal', 'mkd', 'ru', 'ua']
org.freedesktop.ibus.general preload-engines ['xkb:es::spa', 'xkb:us::eng', 'xkb:il::heb']
org.freedesktop.ibus.general engines-order ['xkb:es::spa', 'xkb:il::heb', 'xkb:us::eng']