Air and defrost doors

[mingoman]

I pulled my dash today and found both control doors out of the small holes they should be in and just hanging. One of the doors wasn't even hooked to the control rod for it.
It wasn't that hard to get the doors back in place or pop the control are back on, but I'm left with how they got in that shape in the first place.
Has anyone else had this problem? Anything I can do to help them stay in place while I've got the dash off? Also, is there anything I need to change out while I've got this off? Thanks.