Don't you hate when..

[PbFut]

you get everything back together, look over to see a screw or washer left over.
I just finished riveting back together my passenger vent window. Went to place the spring and nut assembly on the window stud and realized I forgot that the rotation limiting washer must be first placed on the stud BEFORE you rivet the window onto the frame. And of course, the rebuild kit only comes with 1 of these step rivets per side.