Linux Mint Alt + F4 not working/Incorrect keyboard layout   

The keyboard combination of ALT + F4 stopped working after upgrade to Linux Mint 19 ( from Linux Mint 17). Actually it was working unexpectedly:

• it's switching to TT4
• close the current window

Before it was closing the window without any other actions. I notice also some of the keyboard combination we not working as well. I searched for possible reasons and solutions and this is what I found:

• Enabled Fn key might cause this problem

  • In order to disable function key on your keyboard you can press the Fn + Escape (for most laptops)

• The second reason which might cause the issue is related to keyboard setup

  • In order to fix it you need to type in terminal:

sudo kbd_mode -s

and now ALT + F4 should work normally.

What happen in this case? The keyboard mode is changed. You can check the current keyboard setup by:

sudo kbd_mode

In my case the modes were:

• xlate (8-bit) mode
• raw (scancode) mode

More info about the problem:

• Incorrect keyboard layout
• Alt + F4 switches to TTY4