When you try to craft something by dragging the items around, they don't stay in the crafting grid IF you have the exact amount

Example :
Take at least 4 wood planks, and craft wooden slabs by dragging them in the grid, no problem.
Do it again with THREE planks, you can't, they stay in your cursor.

It does that with a lot of crafts, so I assume it does for all. It does that with and without the crafting table.