When any block is selected in the beacon GUI, the block is not shaded correctly.
Blocks grow bright when in a activated beacon GUI
Block in inventory
Inventory in Beacon
Holding a block while in the beacon GUI messes with the texture.
Inventory item light glitch when in the beacon configuration dialog
Block icons brighten when moving in beacon GUI
1.4 Bug: Blocks loose their shading in the Beacon GUI
Enchanted items show its background on the beacon-block