Tony Williams wrote:

I think you have (or I may have). The little demo window one
salesman had had the two glass sheets sandwiched onto a plastic
frame (and the whole sandwich then dropped as a complete assembly
into the main window frame). I'm fairly certain I saw drain slots,
along the base of the sandwich, opening up to the airgap between the
glass sheets.

That would be a most unusual arrangement - apart from anything
else, they'd be permanently misted up! Are you sure the sealed
unit had slots at the bottom?

--
Grunff