How to make a breakable window?

[Daemian]

On level editor, go to static objects, select mansion base from the list and place the object called window_noglass. That one has no glass.

You gotta put a breakable window yourself, I think it's this one: mansionbase_large_window_breakable.ent
Try setting its life to -1 and see if it breaks, If it does, you can use it.

Then add some glass particles and sounds when it breaks.
I don't remember if that entity needs a collide callback to break, you should throw something at it and check.