### I'm opening this issue because:

- [ ] I'll report a bug
- [ ] I'll propose a new feature

### Description

### Failure Information (for bugs)

#### Steps to Reproduce

Please provide detailed steps for reproducing the issue.

1. step 1
2. step 2
3. you get it...

#### System configuration

- Operating system:
- Firefox version:
- Vim-Vixen version:

#### Console logs

Any relevant log in developer tools: