Probably not the first, but I found out that light gray stained glass panes are invisible in inventory : r/Minecraft
Minecraft Survival: How to Make Light Gray Stained Glass Pane
Let's play Where's the light grey glass pane? : r/Minecraft
Door – Minecraft Wiki
Light Gray Stained Glass Pane, Minecraft Universe Wiki
Iron Bars – Minecraft Wiki
Minecraft Survival: How to Make Light Gray Stained Glass Pane
Crafted Blocks
Melody's Stained Glass Minecraft Texture Pack
light gray stained glass pane or light grey stained glass pane? : r /PhoenixSC
Glass – Minecraft Wiki
Probably not the first, but I found out that light gray stained glass panes are invisible in inventory : r/Minecraft
How to craft glass in Minecraft?