Question: **Note: I am using the Gnome desktop environment**

My laptop keyboard has only the keys it needs, and few of the normal compose keys available. I use them all.
I'd like to set the compose key to `End`, but it's not on the list in Gnome Tweak Tool:

[![enter image description here](https://i.stack.imgur.com/vgS5l.png)](https://i.stack.imgur.com/vgS5l.png)

How can I set the compose key to `End`?

Answer: 
I solved the problem with help from [@chaskes](https://askubuntu.com/users/117123/chaskes):

```
xmodmap -e "keycode 115 = Multi_key End"

```

remapped the first level of `End` to the compose key, but allows me to press `Shift`-`End` to send an actual `End` keypress.
I made this permanent by putting it in my `~/.xinitrc`.

Other sources:  

<https://unix.stackexchange.com/a/109472/>  

<https://askubuntu.com/a/24930/>
On my system, the *insert* key is totally useless. Touching it could only create typing errors. And the name makes sense for a Compose key.

xev told me that the *insert* key is keycode 118.

So my ~/.xmodmap is 2 lines:

```

keycode 118 = Multi_key
! Insert key is Compose key.

```

And for backup, I execute this in my startup file:

```

xmodmap -e "keycode 118 = Multi_key"

```

I don't really know if **both** changes were necessary, but it works perfectly and I don't feel like messing with it.