Do you often find yourself in the situation that you are resizing windows to make sure you can fit multiple windows next to each other on the screen? This add-on resizes the browser window to the most ideal size for the site you are on. It currently supports:
If you would like to add more sites, I am looking forward to your pull request at https://github.com/kewisch/ideal-size. You can also get in touch using a github issue or the support email. Be sure to include details about what you believe is the ideal size.
