Due to creating a Datapack I needed a Light Gray Glass Pane.

When I looked for one at the beginning I didn't see it, neither in the Creative Tab, nor in my inventory. Then I found out, that it was just a visual bug. No datapack installed, nor resource pack.

I asked a friend of mine if there is the same issue, and he confirmed it. We found out that its not even having the same texture as the inventory background, so it should be visible anyway.