Roof/windshield part flew off at the highway

[swe370z]

Hi,
I just came home from work, and at the highway on my way home, a roof/windshield part flew off at approx. 90 mph. It's the first time i experience something like this, never heard about this issue before.

I turned around and found the part - in a thousand pieces. So my questions to you professionals:

1. Have you ever experienced something like this, is this a common problem on the 370Z?
3. Should this be fixed through some kind of warranty?
2. If this is not a warranty-question - do you know where i can buy this part? I live in Sweden and the market for stock 370Z-parts isn't especially big here.

Here's a pic of the part missing. Thanks.