Ubuntu 18.04 Keystroke Alt + Shift + (Ctrl) + Down does not work

After upgrade from Ubuntu 16.04 LTS to 18.04 LTS (with unity) the keystrokes Shift + Alt + Down and Alt + Shift + Ctrl + Down stopped working (btw Alt + Shift + (Ctrl) + [Up, Left, Right] works).
I used these keybindings in PHPStorm/Webstorm. In these programs you can search what a key binding does by simply pressing those keys and when I do, Webstorm does not display/catch these keystrokes, like if they were not pressed.
I searched in CompizConfig Settings Manager advanced search in settings value, in the Settings/Keyboard/Shortcuts and with gsettings list-recursively | grep Down and I didn't find anything.
If I press this combo outside of Webstorm Ubuntu does nothing.
Have you any idea where this keybinding could be saved?

PS: I tried this tool (screenkey) to display pressed keys. But it didn't display Alt + Shift + Down or Alt + Shift + Ctrl + Down

Thank you for your help

Gnome Tweaks helps me to fix it!

1. Go to Keyboard & Mouse > Additional Layout Options.

2. Turn off all options for "Switching to another layout".

   

In my case it luckily was just about re-mapping the keys in Settings->Keyboard->Shortcuts.

Here, moving the active window up/down was defined as Shift+Super+Page Up/Down, same without Shift was applied for moving one workspace up/down.

Re-mapping to what I was used to ([Shift+]Ctrl+Alt+Up/Down) did the trick :-)

I had a similar issue recently, while trying to use this keys combination inside vscodium, in Ubuntu 20.04

ctrl + shift + alt + up or down not working as I entend, since it changes the working space instead of the expected function inside a code editor

First approach

Trying to fix it through:

1. Activities > Setting > Keyboard Shortcuts

2. Navigation > Move to workspace above/bellow

didn't work either, because this keys combinition: ctrl + shift + alt + up/down, doesn't show there

Solution

1. install dconf-editior

   sudo add-apt-repository universe # active by default, but just in case
   sudo apt update
   sudo apt install dconf-cli dconf-editor
   

2. go to:

   /org/gnome/desktop/wm/keybindings/move-to-workspace-down
   

3. disable Use default value

4. edit Custom value: by removing

   <Ctrl><Shift><Alt>Down
   

5. Apply

6. follow the same steps for Up (instead of Down)

   /org/gnome/desktop/wm/keybindings/move-to-workspace-up
   

7. log out/in

Result

• you are able to use/bind the keys combinition to whatever you need, (if the editor support it ...)
• you don't lose the workspace navigation feature, since it's still keybond by default to <Supper><PageUp> and <Supper><PageDown> for workspace up and down. and you can actually change this shortcuts, from the keyboard shortcut settings

• https://wiki.ubuntu.com/Keybindings
• https://askubuntu.com/a/575482
• https://askubuntu.com/a/1131849

For Gnome Shell, the workspaces stand in the way. Even the keyboard shortcuts differ a bit to Phpstorm (in my case there was the shift modifier which was not part of the Gnome shell shortcut binding), the workspace up/down block the keybindings in Phpstorm.

So for Gnome Shell, disable dynamic workspaces:

$ dconf write /org/gnome/mutter/dynamic-workspaces false

Set the number of (now static) workspaces to one:

$ dconf write /org/gnome/desktop/wm/preferences/num-workspaces 1

Disable the up/down keyboard shortcuts which are blocking Phpstorm:

$ dconf write /org/gnome/desktop/wm/keybindings/switch-to-workspace-up "['disabled']"
$ dconf write /org/gnome/desktop/wm/keybindings/switch-to-workspace-down "['disabled']"

These fixes are keyboard independent and I can confirm not doing so will have the hotkeys Ctrl+Alt+Shift+Up, Ctrl+Alt+Shift+Down, Ctrl+Alt+Up and Ctrl+Alt+Down not working in Phpstorm as the Gnome Shell blocks them.

I just stumbled over the issue and also kept note in my blog (Gnome Shell Quickfix Cheatsheet).