Pack items into boxes to store more of them.
Mods introducing new content into the game.
More than just chests.
http://puu.sh/qSadM.png
Says it's missing the png for Building Materials from said mod while referencing your mod.
That mod likely adds items to the subgroups I'm generating boxes for, I'll add some checks and use a "missing" icon when it doesn't have one.
Fixed missing icons and added Natural Evolution Buildings icons with 2.0.4.