3d view behind window render...bug?

Hello,

Another question or thing i came across, how do i get the 3d view render to always render trough alpha planes/cubes?
i got 2 buildings with the same window(duplicated) 1 acts normal and is see through but the other one dont even renders the room behind it but everything that is behind that room (screenshot).

is this a bug?


I don’t know, it happens all the time for me. Maybe it’s to prevent Blender from crashing? There are some computer who can’t handle so many alphas

There are some computer who can’t handle so many alphas

This is not it, my computer can handle tons of alpha, if i duplicate more of those buildings all works well. just once every few buildings it does this.

400 trees with 70k alpha planes works verry well. And as you can see it does render the object behind it due to you see the floor at the door, it exist out of the same mesh that does not get rendered behind the window.