@ XanMag:
(joking around, as I myself am the same, super absent-minded as to where I put stuff, grr!)
use some type of container (box/basket, (and/or a hidden spot if worried about home invasion/theft) and then always have/put your keys/wallet/etc important stuff in it (or in that spot). That way, you always know where your stuff is at!
also, I think a good way to describe where the 'Filter -> Show Library Elements' is at:
in the bottom-left corner of the computer screen/quest screen (along with saying that it is 'far' below the left side's "tree of stuff")