**Removing blocks when your inventory is full in build mode will make the undo button appear you can click it but does nothing it has no reason to appear.
If it was already there, if you did it one time one click on undo will do nothing. Two times two times clicking on undo will do nothing (same if you then click on redo)
**
Reproduce:
1. Get your inventory full and get in build mode
2. try to remove a block you don't have in your inventory
3. press undo
you will see it does nothing, it should't even give you a undo for that 'action'
**This bug is very trivial**