Disables the popup alert messages in Google Calendar.
I like to keep Google Calendar open all day so I can get links to Hangouts and make quick edits. I use Fantastical to show me alerts so I don't want Google Calendar trying to show duplicate notifications or using the modal alert dialog that steals the focus from other apps.
This extension simply blocks the alert function for Google Calendar pages. You can view the full source code for the extension on GitHub.