I don't know.

I accidentally deleted the Minecraft folder from my computer, but got it back after a few months. Ever since then, I can't seem to do two things:

Shift-click items in a chest
Craft quickly (extremely laggy crafting)

Even though these things seem small, I would really like my Minecraft to fully work, because I play a lot of Hunger Games servers which involve shift-clicking a lot. Any answers to this problem?