Inventory.contains() always returning false?

Is there something really obvious I’m missing here? I simply have:


I know 100% that I have a stone button in my inventory, so how can this possibly return false?

Update your sponge to the experimental release please. It fixes like all the issues your complaining about.

Well, if that’s the case whatever plugin he’s making won’t work on the recommended builds?

… yes, that’s generally what happens when you use an experimental build