Light Grey Panes of glass appear invisible in the Inventory.

What I expected to happen was to see the Light Grey Pane of glass in my Inventory!

What actually happened was that the Glass Pane was completely invisible in my Inventory, looked like an empty space in the Inventory.

Steps to Reproduce this bug:
1. Open your inventory in Creative Mode and go to Decoration Blocks
2. See the "Empty Space" there
3. That's the Light Grey Glass Pane