What counts as "Windows" for the "Shoot the Glass" Achievement?

Shoot the Glass!

In the Mallcrasher job, destroy all windows in the mall.

What exactly has to be destroyed for this achievement? Only real windows, like from the Stores and Doors, Roof etc or do I need to destroy the glass on the handrails too?

You have to destroy the rail windows, the windows form the store and the small ones that are above, the windows from the third floor (the interior windows), the ceiling windows and even the windows from the gym and from the closed shops. You can even break the windows from the car that is displayed in the car shop but I have no source if that counts towards the goal.