This makes crafting easier by displaying a list of items you can craft using your current inventory. Clicking one of these items will craft this item once, while Shift-Clicking an item will fill the crafting grid once and shift-click the output field to craft as many items as possible.
Also, if you're not sure about a specific recipe, you can enter the (partial) name of the output item in a text box above the recipe list; getting a list of all craftable items that match that name, no matter if you have the ingredients. Moving your mouse to one of these items will show you the recipe.
This mod will not fill the crafting grid more than once per click, so you can't craft your whole inventory at once. This is for the benefit of servers that allow mods, but don't want mods to be able to do "more" than vanilla minecraft - if you want to convert your whole inventory of sugar cane to paper, you'll have to keep shift-clicking the paper icon, converting one crafting grid (3 stacks) at a time.
Version 1.6.7 has a new feature that requests an inventory resync after each craft. It seems like this is a problem when you're playing on servers that are not Spigot/Paper servers. There's a new config option that you can turn on. It's not turned on by default as what it's doing is a bit hacky, and I don't know if there are server plugins (like NoCheatPlus) that don't like it and kick you, or get you banned. So please only turn it on if you have problems.