Command block menu missing command block texture (icon)

Summary:
Before version 1.2, in the command block menu, next to the inscription which type of command block is used, there was a command block icon. But since version 1.2 it is no more. There was nothing in the changelogs about this change.

Steps to reproduce:

1. Place a command block.

2. Open its menu.

3. Look at the inscription of the command block type.

Observed results:
Near the inscription which type of command block is used, there is no corresponding icon.

Expected results:
Near the inscription which type of command block is used, there will be a corresponding command block icon.

Screenshots: