After I buy a spawner with essentials signs, and I put the spawner to another hotbar, and place the spawner, the spawner is gone! If I didn't change the spawner to another hotbar, it won't have this problem. Please fix this as soon a possible. It's so important.

I'm not sure what you mean, I have no issues with dragging spawners between inventories. The spawners we deliver are technically equivalent to the vanilla ones.

Me neither.

Can't repro at all, plus this shouldn't happen since our spawners are identical. Check your other plugins.

Here is the proof:
https://www.youtube.com/watch?v=OL6FndS9yaw

By any chance, do you have SilkSpawners? I used to have the same problem but it stopped after updating it.

I can't reproduce without SilkSpawners, and can't reproduce with latest SilkSpawners. This is not our problem.

Means I have to upgrade silk spawners to the latest version and spigot to the latest version of 1.8.7 to make the spawners work?

Means I have to update my silk spawners to the latest version?

Yeah, or remove it altogether...?

You should also update Spigot as well...?

omg you have to update something to work with newer builds? omgwow