How are the Idaho windows sealed?

Bernie can probably answer this. I purchased plans for the Idaho
quite a while ago, and have been looking them over. The vertical
frames (#21) seem to be a support for both the cabin top and side
windows.

The question I have is how are the windows sealed to prevent leaking?
The plans show them laying over the vertical frames but show no
detail as how the windows are secured in place and sealed to these
frames. (Perhaps I missed something in the plans?) I realize the top
and bottom of the windows are secured in place with the coamings and
carlins, but how about the seams on the sides of the glass? Also,
since the windows are layed on the outside of the supports, I guess
having a natural varnish wood finish wouldn't work too well?

Thanks,
Dennis