In the minecraft 1.5 snapshots, I find there is a bug with the inventory. Since there were features added to that part of the game, when simply trying to pick stuff up and move them, i find myself having to click twice, sometimes the item won't be able to be picked up. I think it has to do with the dragging feature added, it needs tweaking anywho.
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Comments 2
Duplicate of MC-5719.
It seems like if you click an item and move your cursor away too quickly, it doesn't pick up the item.