In Adventure mode you can break some stuff like redstone, glowstonelamps, buttons, glass...

What I expected to happen was...:
That you can't destroy glass, redstone, glowstone...

What actually happened was...:
I destroyed it just like other people on my server (it's in singleplayer and in multiplayer)

Steps to Reproduce:
1. Make sure you can cheat.
2. Place glass
3. Typ /gamemode 2
4. Destroy the glass