Fix Issue #153 Wrong contentInsets when connected mouse

[m1entus]

[dani-mp]

Hi, @m1entus. Thanks for the fix, you're awesome. I couldn't reproduce it in my Mac, but a colleague told me about it. It was happening after item selection, very weird.

Anyway, just setting the scroller type to .Overlay did the fix for me, without having to register for the notification.

[m1entus]

Anyway this will resolve issue when scroller is set to Legacy, end if you connect/reconnect mouse again notification will be called and correct document size will be set ;)

[jwilling]

Thank you for spending the time to put this together. :sparkles:

I just have a couple of comments and questions before I merge this.