Make JS Pop Windows appear in the center of the screen

Problem/Motivation

I was trying to get the JS Pop Window to appear in the center of the screen because selecting items near the edge of the screen enables a horizontal scroll which I want to avoid precisely.

Steps to reproduce

1. Install FullCalendarView.
2. Create a calendar.
3. Configure the display so that the JS Pop Window appears.
4. Add an event near the edge of the screen.
5. Click on the event.

Proposed resolution

Get the information from the user's screen and place the window in the center. For this you have to modify the file: fullcaledar_view.js, precisely the method: eventClick(info).