When you go behind a glass pane or cobblestone wall you can open furnaces, chests. You can also use stuff,you can use crafting tables, stonecutters and all those things. You can also place and break blocks... I made an art gallery then put glass panes in front. After the painting often broke... So I found this glitch... Cobblestone wall glitch was founded by my friend. Perhaps fence too...I don't know...

You can do his when you are 1 block away from the glass.

This is a big glitch...
Breaking stuff behind glass... from 1-2 blocks behind the glass