Fixed an issue with same depth different selector items were stacking improperly
Fixed a bug where the "stickyable" state of items wasn't being cleaned up correctly, resulting in improper stacking and orphans
Fixed a bug when toggling tree items where ".tree-open" was being removed incorrectly

Also updated the sticky header style guide to more accurately represent
true application state (all items are pre-opened via click instead of
hard-coding).