Any form of item sprite loaded on the screen , will cause a 30%~40% FPS drop (not an exaggeration)
That includes opening inventory and containers, crafting, trading, ...ext.
What makes it worst is that item sprites loaded in the hotbar, are also included in this bug, so having any item in the hotbar directly renders the game unplayable in some survival world's.

Please note that you may not notice this if you have a high end device , but on mid and low end devices it is very much noticeable.

(watch the included video , and pay attention to the FPS count)

This bug is a total game breaker , and it must be fixed as soon as possible.