Hoe {CanPlaceOn:[dirt]} Adventure Mode

This is in Adventure Mode
When I use this command: "/give @p wooden_hoe 1 0 {CanPlaceOn:[dirt]}"
I get the hoe fine and I am able to till dirt. dirt has a hitbox and grass doesn't. However, i can still right click on grass to till it.

What I expected to happen was...:
to be only able to till the dirt block.

What actually happened was...:
Able to till Dirt and Grass blocks

Steps to Reproduce:
1. Use "/give @p wooden_hoe 1 0 {CanPlaceOn:[dirt]}"
2. right click on grass block
3. ...

may or may not affect previous versions.