[Plugin: All-in-One Calendar] IE Window shows up when I select data

Still using the 1.5 version.
In IE when I go to calendar to select the date in the admin, a window shows up and ask me if I want to leave the page or not.

I know it might not be a huge problem but since I add lots of events everyday it’s going to slow down my work.

Is there any way to not make it happens?

Thanks

https://www.ads-software.com/extend/plugins/all-in-one-event-calendar/