Summary:
Normally, player can remove top snow with shovel by clicking "use" button (default right button of mouse). However, when there is a block above the top snow, clicking "use" button with shovel does not remove it.

Steps to reproduce:

1. Place top snow on the ground.
2. Place any other block above the top snow.
3. Click "use" button to the top snow with shovel on hand.

Observed results:
Nothing happened.

Expected results:
The top snow will be removed.