When the Command block is at the top of the world, you can't use it by right-clicking on its upper part.

When the Command block is at the top of the world, you can't use it by right-clicking on its upper part.

What I expected to happen was...:
Open the interface and edit the command

What actually happened was...:
All the buttons are grayed out except "Cancel"

Steps to Reproduce:
1. Place a command block at y = 255
2. Right click its upper part