As for the two slots on the left, the tool forge always has four slots, if not all are used they just move to the left and are unused. The rearranging when you choose a tool? Actually just cosmetic, you can produce any tool simply by putting the parts into the right spots.
You'll notice in every tool forge recipe there are always four slots, regardless of how many parts the thing your building has. If you put something in say the lumber axe section in every slot, then switch to say, a throwing knife, you'll see both the other parts are full. (and it'll still be trying to build a lumber axe if you had the correct parts for the lumber axe).
I kinda thought this was the case, thanks guys. Figured I'd confirm. Yeah I don't always bothering clicking the tool buttons; I always know the arrangement for, say, a pickaxe without selecting it.
So I got to the End and forgot to get my bottled End Air, woops. #ThingsToGetDoneTonight. Also when I got to the End I couldn't figure out why there was an army of "Pauls" wrecking the place. It turns out I installed NuclearCraft (which I wanted to try out in lieue of Big Reactors) and that mod adds that silliness by default (configurable).
Collar of Pain is amusing. In experimenting with ways to hurt myself, I found the most quick and reliable was standing on a railcraft rock crusher. Wild guess but I figure I regen around 10 vis per second standing on the crusher, and my armor level probably affects that.
Its not something I'll do often (if ever) but its nice to know that I'll passively regen mana while adventuring amongst a ton of hostile mobs, if such ever happens. With the "railgun crossbow" it doesn't matter much.
What interesting bauble-belts are there? Actually what baubles in general are people sporting?