I am using the vi-mode plugin of oh-my-zsh. In my `.zshrc`, I have

```
bindkey '^[[3~' delete-char

```

where `^[[3~` is the escape code of my delete key. However, this only works in insert mode, but not in command mode. When I type

```
$ abcd

```

move the cursor to the beginning of the line and hit `del` in command mode, I get

```
$ ABCd

```

so apparently the character sequence of the delete key is interpreted literally. How can I make the delete key actually delete a character in command mode?