I was playing the modpack The 1.7.10 Pack through the Technic launcher, and everything was fine, until I pressed some keys and now NEI won't show any items. What might I have done to do this, and how do I fix it?
Mouse over Item Subsets. If you see black boxes, doubleclick on them to restore them to the item search.
This is an item filtering feature. If, for example, you don't want Forge Microblocks to show up in item searching, mouse over Item Subsets, then Creative Tabs, then Forge Microblocks. With the mouse still over the Forge Microblocks button, you can right-click to disable all Forge Microblocks from showing up in item search.