Drop-down tag list?

[kindlin]

I've been trying to incorporate xtomxfallsx's drop-down tags list tutorial for Component into my layout myself to no avail. I haven't see this tutorial in this community either, so I was wondering if anyone knows how to make a drop-down list for tags in the sidebar. Help please?

PS: my layout is customized based on dooped's code & I'm using the updated version of Flexible Squares.