Firefox Alt key not working in keybinds #749

• code-server version: 1.1119-vsc1.33.1
• OS Version: Linux 4.19.36_1 x86_64
• Browser version: GNU IceCat 60.3.0esr 64-bit

Description

Making a keybinding like Ctrl+Alt+R doesn't work. You can't type Alt into the create keybind input box, so clicking Ctrl+Alt+R will only result in Ctrl+R being displayed.

If something registers a keybind with Alt in it, it doesn't work either.

Strangely, using editor keybinds like Alt+Up or Alt+Down to move a line work properly (these show up in keybindings list). I tried to use Ctrl+Alt+R while focused on the editor, and it still didn't work.

Steps to Reproduce

1. Go to keybinding settings
2. Edit some keybinding and try to set it to Ctrl+Alt+R
3. Notice that it shows Ctrl+R instead of what you'd expect