why isn't glass material transparent?

[cbt990]

[ToanDN]

Edit the window family, select the Opening Cut and set to Transparent in 3D (and Elevation if you need them to be transparent in Elevation views).

[cbt990]

I have a related question.

Why does this glass appear transparent:

But this is shaded? 

[ToanDN · Accepted solution]

The second one is faulty.  Don't use it.

[cbt990]

i Deleted the faulty material from the model and transferred the correct one over.