"Add termin down" closes terminal if one terminal is maximized

[Syphdias]

I guess this happens because the shortcut is not caught by tilix and thus results in just being interpreted by the terminal as ctrl-d (which closes the session).

It would be nice if it would instead quit maximize (and optionally open a new terminal).

Steps to reproduce:

1. Open two terminal sessions in one tilix window
2. Maximize one terminal
3. Optional: Do important stuff and forget you maximized the terminal you are in
4. Press alt-shift-d to open another terminal

❯ tilix --version
Versions
	Tilix version: 1.8.9
	VTE version: 0.54
	GTK Version: 3.24.5

Tilix Special Features
	Notifications enabled=0
	Triggers enabled=0
	Badges enabled=1
❯ dconf dump /com/gexperts/Tilix/keybindings/
[/]
terminal-advanced-paste='<Primary><Shift>v'
session-add-right='<Primary><Shift>e'
session-name='<Primary><Alt>w'
session-save-as='<Primary><Alt>x'
session-add-down='<Primary><Shift>d'
terminal-paste='disabled'
session-open='<Shift><Ctrl>o'

PS: As you can see from the output of dconf I use ctrl-shift-d which has the same problem

[doniks]

fwiw still true

tilix --version
Versions
	Tilix version: 1.9.4
	VTE version: 0.68
	GTK Version: 3.24.33

Tilix Special Features

	Notifications enabled=0
	Triggers enabled=0
	Badges enabled=1