In survival when you open the crafting interface. . . the names of items are incorrect . . . All the slabs names say tile.stoneSlab.name<, melon seeds in crafting say: item.seedsMelon.name<, and finaly dyes and lapis say: item.dyePowder.name< . . . . .

In creative mode when you select the slabs the name is: tile.stoneSlab.name<