In tweakeroo you implement something(MixinEditSignScreen.java) as openGui(null)
But in malilib, closeGUI has changed from mc.openScreen(null) to onClose().
Maybe we should implement openGui(null) as onClose()?

In minecraft source code they are just the same thing.
However, openScreen(null) acts slightly different from manualy press Esc, which is, somtimes a ghost screen still exists. I will try to figure out the difference.

For signs, it's ok to use openScreen(null).
For containers(include villagers), I should use minecraft.player.closeContainer.