In my Ubuntu 18.04, I set switching languages by Super+Space, as shown in
Settings->Devices->Keyboard->"Switch to next input source"
and in the picture below, but it doesn't allow me to change keyboard layout with Alt+Shift as I used to do.
I can do it using Gnome Tweaks as shown below:
When I press Alt+Shift, the language is switching but the language chooser doesn't appear, unlike Super+Space as per picture below:
How can I have language chooser shown by pressing Alt+Shift, please?