When the item in my first hotbar slot (a pickaxe) breaks, I cannot add a new pickaxe or any other tool to that hotbar slot eventhough it is now empty. Every time I try to assign a new item it simply pops back onto my cursor again and is not actually put down into the slot. I have to save & exit out of the world and enter again to remedy this, but every time the tool breaks the same bug appears.

This happens regardless of if my inventory is full or not. 

So far this has only happened with the very first slot in the hotbar. I tried to put the pickaxe in the second hotbar slot and when it broke I could replace it no problem, but when I again tried to use the first hotbar slot after this the problem persisted. 

I play privately in a single-player world.

I have tried to completely turn off the game and restart it, but it doesn't help. As soon as the pickaxe breaks I can't replace it.

The game is up-to-date.